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24th Annual Gulf Coast Section SEPM Foundation Bob F. Perkins Research Conference—2004 i

Salt-Sediment Interactions and Hydrocarbon Prospectivity:Concepts, Applications, and

Case Studies for the 21st Century

24th Annual Gulf Coast Section SEPM FoundationBob F. Perkins Research Conference

2004

Program and Abstracts

Houston Marriott WestchaseHouston, Texas

December 5–8, 2004

Edited by

Paul J. Post, Donald L. Olson, Kevin T. Lyons, Stephen L. Palmes,

Peter F. Harrison, and Norman C. Rosen

ii Program and Abstracts

Copyright © 2004 by theGulf Coast Section SEPM Foundation

www.gcssepm.org

Published December 2004

http://www.gcssepm.org/

24th Annual Gulf Coast Section SEPM Foundation Bob F. Perkins Research Conference—2004 iii

Foreword

It had been too long. It was time: time forsomeone to propose, develop, and organize thisconference. In 1995, GCSSEPM’s 16th Bob F.Perkins Research Conference, “Salt, Sediment andHydrocarbons” was held, and AAPG published “SaltTectonics: a Global Perspective” with papersdeveloped from a symposium held in 1993. TheGeological Society published “Salt Tectonics” in1996; and “Salt, Shale and Igneous Diapirs in andaround Europe” in 1999. Five to ten years in theevolution of our knowledge of salt tectonics is toolong. Concepts evolve and change. Salt moves.

To everyone who responded to an e-mailpromising “If the conference goes well, you will earnthe undying gratitude of the geological community”from someone they either knew, knew casually, orhad no idea who was sending them the e-mail, yetagreed to serve as either a Program AdvisoryCommittee Co-chair or a member of the ProgramAdvisory Committee, thank you. Without each ofyou, your encouragement, advice, or paper, thisconference would not have come into being.

We originally planned this conference around aseries of themes that built upon each other.Unfortunately, as is often the case in life, our nice,neat themes did not correspond to the reality of whatauthors were able to provide. Consequently, for thefinal program, rather than force manuscripts into ourthemes, we altered the themes to fit the manuscripts.Mark Rowan, with his extensive knowledge of mostof the authors, their backgrounds, and work, wasinstrumental in this retrofitting.

In today’s exploration and productionenvironment, and to some extent academia, there isseldom time to write papers. Many reasons aregiven, among them the fact that taking the time towrite papers is seldom in anyone’s yearly goals, andmeeting and/or exceeding these can go a long waytowards determining one’s continued employment,or as someone said, “Real work gets in the way ofgood science.” In addition to the time constraintsthere are increasing legal complexities necessary toobtain permissions from management, partners, anddata owners. The hassle of publishing a paper soonbecomes outrageous. Since GCSSEPM takes greatpride in enriching the literature so that those whocannot attend our research conferences can benefitfrom the papers included in our programs via ourconference CDs, the authors of all of these paperswho devoted their time to produce them, often onweekends and after work, are the most importantcomponent of our research conferences. To each

author and co-author, my sincerest thanks. Withoutyour efforts, there would be no conference. On asimilar note, my thanks to those companies andorganizations that were supportive of members oftheir staff taking the time to write manuscripts andprovide poster and oral presentations. Thepersistent efforts of authors, their organizations, andoften their legal staffs, to obtain partner and/orgovernment permissions to provide papers, wasinvaluable. To those vendors who allowed their datato be shown, my thanks.

To make it easier for authors to accept andincorporate reviews and edits, rather than editinghard copies, we requested that as many of ourauthors as possible submit their papers as MS Worddocuments. We circulated these to the editors andreturned a single file to the lead author reflecting thework of all the reviewers. Our goal was to try to makethe process of incorporating editorial changes assimple and time efficient as possible for the authors.They received a single MS Word copy back, couldelect to hit the “Accept Changes” on the ReviewingToolbar, and off they went, no more going from hardcopy to hard copy trying to figure out which editor’scomments to incorporate. It worked, or at leastseemed to work, based on the comments wereceived from the authors.

Even the best writers need editors.Consequently, I would like to thank my MineralsManagement Service colleagues, Don Olson, KevinLyons, Stephen Palmes, and Pete Harrison, whoserved as editors. Without their work, reviewing andediting 48 papers would have been impossible. Weeach learned from the experience. MineralsManagement Service supported our efforts; allowingus to edit during work hours.

Norm Rosen encouraged me to convene thisconference, and did his usual excellent job as finaleditor, so to one of my oldest and dearest friends,Norm, thank you. Even before Norm, Ed Picou wasmy sounding board regarding whether or not toconsider attempting to convene this conference.Without his encouragement, I would never haveundertaken this task. Minerals Management Servicegraciously allowed me to work on this conference aspart of my duties.

My thanks to Ms. Jerri Fillon, who handles AVand is the calm in the eye of the chaos/frayednerves/churning stomachs that can occasionally bethe speakers’ table. To all those “shoe maker’selves” who stuff bags, work at the registration table,

iv Program and Abstracts

and generally make sure that everything is done:without you, this parade does not hit the streets; toeach of you my sincerest thanks.

To those few of you who actually readForewords and the like, I trust I have not kept you toolong from your real goal, the papers of this, the

GCSSEPM 24th Bob F. Perkins ResearchConference, Salt-Sediment Interactions andHydrocarbon Prospectivity: Concepts, Applications,and Case Studies for the 21st Century. Enjoy thefruits of our labors.

Paul J. Post

24th Annual Gulf Coast Section SEPM Foundation Bob F. Perkins Research Conference—2004 v

GCSSEPM Foundation

Trustees and Executive Director

Nancy Engelhardt-Moore, ChairwomanGeoFix-It ConsultingHouston, Texas

Rashel N. RosenMicropaleontological Consultant

Michael J. StyzenShell E&P Deepwater ServicesNew Orleans, Louisiana

Paul Weimer

University of Colorado

Boulder, Colorado

Norman C. Rosen, Executive Director

NCR & Associates

Houston, Texas

Executive Council

PresidentJory A. PachtSeis-Strat ServicesHouston, Texas

President ElectRobert LoucksBureau of Economic GeologyAustin, Texas

Vice PresidentBonnie R. WeisePYR Energy CorporationSan Antonio, Texas

Secretary

Lana Czerniakowski

ConocoPhillips

Houston, Texas

Treasurer

Patricia Santogrossi

Consultant

Houston, Texas

Past-President

Richard Fillon

Earth Studies Associates

New Orleans, Lousiana

Audio-Visual and Poster Committee

Nancy Engelhardt-Moore (Chairwoman)GeoFix-It ConsultingHouston, Texas

Jerri FillonEarth Studies AssociatesNew Orleans, Louisiana

Arden CallenderApplied BiostratigraphixHouston, Texas

Michael J. NaultApplied BiostratigraphixHouston, Texas

Program Advisory Committee Co-Chairs

Paul J. PostMinerals Management Service

William H. HartBP

Martin P. A. JacksonBureau of Economic GeologyUniversity of Texas

Ulisses T. MelloIBM & Lamont-Doherty

Stephen L. PalmesMinerals Management Service

Frank J. PeelBHP Billiton

Mark G. RowanRowan Consulting, Inc.

Gábor TariVanco Energy Company

vi Program and Abstracts

Program Advisory CommitteeMartin L. Albertin BP

Tim Ford Newfield

Katherine A. Giles New Mexico State University

Chris Hedlund Shell International E&P

Michael R. Hudec Bureau of Economic GeologyUniversity of Texas

S. Jerry Kapoor WesternGeco

Louis M. Liro Veritas DGC Inc.Kevin T. Lyons Minerals Management ServiceMike Roberts ChevronTexacoRoger Sassen Geochemical and Environmental ResearchGroupTexas A&M University

Bruno C. Vendeville Bureau of Economic GeologyUniversity of TexasIan A. Watson ExxonMobil

24th Annual Gulf Coast Section SEPM Foundation Bob F. Perkins Research Conference—2004 vii

Contributors to the GCSSEPM Foundation

Sponsorship Categories

Please accept an invitation from the GCSSEPM Section and Foundation to support Geological andGeophysical Staff and Graduate Student Education in Advanced Applications of Geological Research toPractical Problems of Exploration, Production, and Development Geology.

The GCSSEPM Foundation is not part of the SEPM Foundation. In order to keep our conferences priced ata low level and to provide funding for university staff projects and graduate scholarships, we must haveindustry support. The GCSSEPM Foundation provides several categories of sponsorship. In addition, you mayspecify, if you wish, that your donation be applied to Staff support, Graduate support, or support of ourConferences. Please take a moment and review our new sponsor categories for 2004, as well as our currentand past sponsors. In addition, we ask that you visit our sponsors’ Web sites by clicking on their logo or name.Thank you for your support.

Corporate Sponsorships

Diamond($15,000 or more)

Platinum

($10,000 to $14,999)

Gold

($6,000 to $9,999)

Silver($4,000 to $5,999)

Bronze

($2,000 to $3,999)

Patron

($1000 to $1,999)

Individuals & Sole Proprietorships

Diamond($3,000 or more)

Platinum

($2,000 to $2,999)

Gold

($1,000 to $1,999)

Silver($500 to $999)

Bronze

($300 to $499)

Patron

($100 to $299)

Sponsor Acknowledgment

All sponsors will be prominently acknowledged on a special page inserted in the 2004 and 2005 ConferenceAbstracts volume and CDs, and with large placards strategically placed throughout the meeting areas duringthese conferences.

Corporate-level Diamond sponsors will be acknowledged by having their logo displayed on the back jewelbox cover of the Conference CD. Corporate level Platinum sponsors will be acknowledged by having theirlogo placed on the first page of the CD. All contributions used for scholarships and/or grants will be givenwith acknowledgment of source.

In addition to the recognition provided to our sponsors in GCSSEPM publications, we proudly provide alink to our sponsors’ Web site. Just click on their logo or name to visit respective GCSSEPM sponsors.

The GCSSEPM Foundation is a 501(c)(3) exempt organization. Contributions to it are tax deductible ascharitable gifts and contributions.

For additional information about making a donation as a sponsor or patron, please contact Dr. Norman C.Rosen, Executive Director, GCSSEPM Foundation, 2719 S. Southern Oaks Drive, Houston, TX 77068-2610.Telephone (voice or fax) 281-586-0833 or e-mail at [email protected].

mailto:[email protected]

viii Program and Abstracts

2004 Sponsors

Corporate SponsorshipsSilver

Individuals & Sole ProprietorshipsSilver

Michael J. NaultEd Picou

BronzeAlan Lowrie

http://www.shell.com/

http://www.conocophillips.com/

http://www.eogresources.com/

http://www.hess.com/

http://www.bhpbilliton.com/

24th Annual Gulf Coast Section SEPM Foundation Bob F. Perkins Research Conference—2004 ix

2003 Sponsors

Corporate Sponsorships

Silver

Bronze

Patron

Winn ExplorationIndividuals & Sole Proprietorships

SilverMichael J. Nault

Edward B. Picou, Jr.

PatronPaul J. Post

MidAmerica Business UnitUpstream Technology

South Texas Business Unit

Energy Services


http://www.eogresources.com/

http://www.chevrontexaco.com

http://www.exxonmobil.com/

http://www.schlumberger.com


http://www.halliburton.com/

http://www.roxar.com/

x Program and Abstracts

Credits

Graphics Design and CD ROM Publishing by

Houston, Texaswww.bergan.com

Cover Image and Opening AnimationThe cover image on the jewel case insert is from Ings et al., Figure 4; specifically, the top image, which is

a still image from his Model 2, demonstrating no density contrast between salt and overburden. The coverimage on the Abstracts volume is from the entire Figure 4, comparing Model 2 and Model 1.

The opening animation for the CD is from Ings et al., Animation 5, which demonstrates local isostaticcompensation for the weight of the salt and sediments and assumed water loading above the sediments to thelevel of the prograding shelf.

http://bergan.com

http://bergan.com

24th Annual Gulf Coast Section SEPM Foundation Bob F. Perkins Research Conference—2004 xi

Salt-Sediment Interactions and Hydrocarbon Prospectivity:Concepts, Applications, and Case Studies for the 21st Century

24th Annual Gulf Coast Section SEPM FoundationBob F. Perkins Research Conference

Houston Marriott WestchaseHouston, Texas

December 5–8, 2004

Program

Sunday, December 5, 2004

4:00-6:00 pm Registration (Grand Foyer) and Poster Setup (Grand Pavilion)

6:00-8:00 pm Welcoming Reception and Poster Preview (Grand Pavilion)

Monday, December 6, 2004

7:00 am Continuous Registration (Grand Foyer)

8:00 am Welcome: Nancy Engelhardt-Moore, Chair of the Board of Trustees, GCSSEPM Foundation (Grand Pavilion)

8:05 am Introduction and Welcome: Paul Post, Program Chair (Grand Pavilion)

Keynote Address

Co-Chairs: S.J. Kapoor and U.T. Mello

8:25 am Hudec, Michael R. and Jackson, Martin P. A.

Salt Tectonics in the New Millennium: Navigating the Information Flood ...................... 1

Session I—New Techniques in Modeling and Salt Body Delineation

8:50 am Mello, Ulisses T.; Pereira, Sebastião C. A.; de Mendonça, Jorge M.; and Rodrigues, José R. P.

On Integrating Salt Motion in Basin Modeling: A Hybrid Approach for Goal-Oriented Salt Flow ............................................................................................................ 2

xii Program and Abstracts

9:15 am Kapoor, S. Jerry and Albertin, Uwe, K.

Integrating Complementary Tools for Depth Imaging ..................................................... 3

9:40 am Refreshment Break and Posters

Session I—New Techniques in Modeling and Salt Body Delineation (Cont.)

Co-Chairs: P.F. Harrison and W.H. Hart

10:05 am Ings, Steven; Beaumont, Christopher; and Gemmer, Lykke

Numerical Modeling of Salt Tectonics on Passive Continental Margins: Preliminary Assessment of the Effects of Sediment Loading, Buoyancy, Margin Tilt, and Isostasy .... 4

Session II—Diapirs and Allochthonous Salt

10:30 am Dyson, Ian A. and Rowan, Mark G.

Geology of a Welded Diapir and Flanking Mini-Basins in the Flinders Ranges of South Australia .................................................................................................................. 5

10:55 am Mohr, Markus; Kukla, Peter A.; Urai, Janos L.; and Bresser, Georg

New Insights to the Evolution and Mechanisms of Salt Tectonics in the Central European Basin System: An Integrated Modeling Study from Northwest Germany ........ 6

11:20 am Hudec, Michael R.

Salt Intrusion: Time for a Comeback? .............................................................................. 7

11:45 am Dyson, Ian A.

Christmas Tree Diapirs and Development of Hydrocarbon Reservoirs: A Model from the Adelaide Geosyncline, South Australia ................................................ 8

12:05–1:30 pm Lunch and Open Poster Booths

Session II—Diapirs and Allochthonous Salt (Cont.)

Co-Chairs: L.M. Liro and C. Hedlund

1:30 pm Hart, William; Jaminski, Jacek; and Albertin, Martin

Recognition and Exploration Significance of Supra-Salt Stratal Carapaces ................... 9

1:55 pm Liro, Louis M.; Murillas, Joseba; Villalobos, Lorenzo; Gatenby, Glen; and Mathur, Vinod

Salt Sutures in Single- and Multi-Tiered Allochthons, Green Canyon and Walker Ridge Areas, Deep Water Gulf of Mexico ................................................................................. 10

2:20 pm Jackson, Martin P. A. and Hudec, Michael R.

A New Mechanism for Advance of Allochthonous Salt Sheets ........................................ 11

2:45 pm Harrison, Holly; Kuhmichel, Lew; Heppard, Phil; Milkov, Alexei V.; Turner, Joshua C.; and Greeley, Dave

Base of Salt Structure and Stratigraphy—Data and Models from Pompano Field, VK 989/990, Gulf of Mexico ........................................................................................... 12

3:10 pm Refreshment Break and Posters

24th Annual Gulf Coast Section SEPM Foundation Bob F. Perkins Research Conference—2004 xiii

Session III—Extension and Inversion

Co-Chairs: D.L. Olson and M.G. Rowan

3:35 pm Le Calvez, Joël H. and Vendeville, Bruno C.

Map Patterns of Rafted Blocks in Outcrops and Experimental Models ......................... 13

4:00 pm Fiduk, Joseph C.; Anderson, Lynn E.; and Rowan, Mark G.

The Wilcox Raft: An Example of Extensional Raft Tectonics in South Texas, Northwestern Onshore Gulf of Mexico ........................................................................... 14

4:25 pm Banbury, Nick and Underhill, John

The Role of Halokinesis in Supra-Salt Fault Development: Insights from the North Sea ......................................................................................................................... 15

4:50 pm Krzywiec, Piotr

Basement vs. Salt Tectonics and Salt-Sediment Interaction—Case Study of the Mesozoic Evolution of the Intracontinental Mid-Polish Trough .................................... 16

5:30–8:00 pm Hot Buffet and Poster Session (Sessions will end at 5:15)

Tuesday, December 7, 2004

Session IV—Salt, Hydrocarbons, and Brines

Co-Chairs: M.P.A. Jackson and I. Watson

8:00 am Roberts, Michael J.; Metzgar, Craig R.; Liu, Jianchang; and Lim, Siang J.

Regional Assessment of Salt Weld Timing, Campos Basin, Brazil ................................. 17

8:25 am Rowan, Mark G.

Do Salt Welds Seal? ........................................................................................................ 18

8:50 am Heggland, Roar

Hydrocarbon Migration and Accumulation Above Salt Domes—Risking of Prospects by the Use of Gas Chimneys ............................................................................................ 19

9:15 am Shaker, Selim S.

Geopressure Compartmentalization in Salt Basins: Their Assessment for Hydro-carbon Entrapments in the Gulf of Mexico ..................................................................... 20

9:40 am Refreshment Break and Posters

Session IV—Salt, Hydrocarbons, and Brines (Cont.)

Co-Chairs: K.T. Lyons and R. Sassen

10:05 am Sassen, Roger; Sweet, Stephen T.; DeFreitas, Debra A.; Eaker, Nancy L.; Roberts, Harry H.; and Zhang, Chuanlun

Brine Vents on the Gulf of Mexico Slope: Hydrocarbons, Carbonate-Barite-Uranium Mineralization, Red Beds, and Life in an Extreme Environment .................................... 21

xiv Program and Abstracts

10:30 am Hanor, Jeffrey S.

The Role of Salt Dissolution in the Geologic, Hydrologic, and Diagenetic Evolution of the Northern Gulf of Mexico Sedimentary Basin ........................................................ 22

Session V—The Role of Salt in Regional and Basin-Scale Tectonics

10:55 am Shimeld, John

A Comparison of Salt Tectonic Subprovinces Beneath the Scotian Slope and Laurentian Fan ............................................................................................................... 23

11:20 am Unternehr, Patrick and de Clarens, Philippe

A Comparison Between the Salt Basins of the Gulf of Mexico and the South Atlantic . 24

11:45 am Mohriak, Webster U.; Biassusi, A. S.; and Fernandez, B.

Salt Tectonic Domains and Structural Provinces: Analogies Between the South Atlantic and the Gulf of Mexico ...................................................................................... 25

12:05–1:30 pm Lunch and Open Poster Booths

Session V—The Role of Salt in Regional and Basin-Scale Tectonics (Cont.)

Co-Chairs: G. Tari and M.L. Albertin

1:30 pm Marton, Gyorgy; Schoenborn, Greg; Carpenter, Danielle; and Cool, Thomas

Salt Tectonics of the Continent-Ocean Transition, Deep-Water Angola ........................ 26

1:55 pm Tari, Gabor; Coterill, Katrina; Molnar, Jim; Valasek, Dave; Walters, Gary; and Alvarez, Yves

Salt Tectonics and Sedimentation in the Offshore Majunga Basin, Madagascar .......... 27

2:20 pm Fiduk, Joseph C.; Brush, Eugene R.; Anderson, Lynn E.; Gibbs, Peter B.; and Rowan, Mark G.

Salt Deformation, Magmatism, and Hydrocarbon Prospectivity in the Espirito Santo Basin, Offshore Brazil ..................................................................................................... 28

2:45 pm Trudgill, Bruce; Banbury, Nick; and Underhill, John

Salt Evolution as a Control on Structural and Stratigraphic Systems: Northern Paradox Foreland Basin, Southeast Utah, USA ............................................................. 29

3:10 pm Refreshment Break and Posters

Session VI—Salt in Contractional Settings (Foldbelts)

Co-Chairs: P.J. Post and M.J. Roberts

3:35 pm Szatmari, Peter; Viana, Adriano R.; Da Silveira, Desiderior P.; Duarte, Cláudio S.L.; de Freitas, João T.R.; Gamboa, Luiz Antonio P.; Machado, Marco Antônio P.; de Moraes, Marcos F.B.; Carlotto, Marco Antônio; Pereira, Sergio R.; and Gil, João A.

Compressional Salt Tectonics: Processes and Pitfalls ................................................... 30

4:00 pm Gottschalk, Richard R.; Anderson, Arlene V.; Walker, James D.; and Da Silva, Joaquim C.

Modes of Contractional Salt Tectonics in Angola Block 33, Lower Congo Basin, West Africa ...................................................................................................................... 31

24th Annual Gulf Coast Section SEPM Foundation Bob F. Perkins Research Conference—2004 xv

4:25 pm Jackson, Martin P. A.; Hudec, Michael R.; and Jennette, David C.Insights from a Gravity-Driven Linked System in Deep-Water Lower Congo Basin, Gabon .............................................................................................................................. 32

4:50 pm Letouzey, Jean and Sherkati, ShahramSalt Movement, Tectonic Events, and Structural Style in the Central Zagros Fold and Thrust Belt (Iran) ............................................................................................................ 33

5:30–8:00 pm Beer, Wine, Snacks, and Poster Session (Sessions will end at 5:15)

8:00 pm Authors Remove Posters(Contractor will remove display boards at 8:15 pm)

Wednesday, December 8, 2004

Session VII—Shale Tectonics

Co-Chairs: S.L. Palmes and L.J. Wood

8:00 am Palmes, Stephen L.Shale-Detached Deformation along the Texas Shelf: 3D Analyses, Recognition Criteria, and Development of Duplex Structures in Extensional Settings ...................... 34

8:25 am Camerlo, Rion; Meyer, David; and Meltz, RobertShale Tectonism in the Northern Port Isabel Fold Belt .................................................. 35

8:50 am Sullivan, Sean; Wood, Lesli J.; and Mann, PaulDistribution, Nature and Origin of Mobile Mud Features Offshore Trinidad ............... 36

9:15 am Deville, Eric; Battani, Anne; Callec, Yannick; Guerlais, Sophie-Hélène; Mascle, Alain; Prinzhofer, Alain; Schmitz, Julien; and Lallemant, Siegfried

Processes of Mud Volcanism and Shale Mobilization: A Structural, Thermal and Geochemical Approach in the Barbados-Trinidad Compressional System .................... 37

9:40 am Refreshment Break

Session VII—Shale Tectonics (Cont.)

Co-Chairs: K.A. Giles and M.R. Hudec

10:05 am Wood, Lesli J.; Sullivan, Sean; and Mann, PaulInfluence of Mobile Shales in the Creation of Successful Hydrocarbon Basins ............ 38

Session VIII—Salt-Sediment Interaction

10:30 am Matthews, Wendy; Hampson, Gary; Trudgill, Bruce; and Underhill, JohnImpact of Salt Movement on Fluvio-Lacustrine Stratigraphy and Facies Architecture: Late Triassic Chinle Formation, Northern Paradox Basin, Southeast Utah, USA ......... 39

10:55 am Byrd, Tom; Meisling, Kristian; Jaffey, Noah; Vines, John; Buddin, Tim; and Ekstrand, Eric

3D Structural Restoration of Ponded-Basin Turbidite Reservoirs in a Linked Extensional-Compressional Salt Basin, Holstein Field, Deep-Water Gulf of Mexico .... 40

xvi Program and Abstracts

11:20 am Dyson, Ian A.Interpreted Shallow and Deep-Water Depositional Systems of the Beltana Mini-Basin in the Northern Flinders Ranges, South Australia .......................................................... 41

11:45 am Davison, IanBathymetric Control on Paleocene Gravity Flows Around Salt Domes in the Central Graben, North Sea .......................................................................................................... 42

12:05–1:30 pm Lunch

Session VIII—Salt-Sediment Interaction (Cont.)

Co-Chairs: T. Ford and F.J. Peel

1:30 pm Giles, Katherine A.; Lawton, Timothy F.; and Rowan, Mark G.Summary of Halokinetic Sequence Characteristics from Outcrop Studies of La Popa Salt Basin, Northeastern Mexico .................................................................................... 43

1:55 pm Eisenberg, Richard A.; Combs, Wes; Johnson, Matthew; and Eastham, KevinPetroleum Systems Analysis and Comparison of Inversion Structures (Turtles and Half Turtles), Eastern Salt Canopy Trend: Deepwater Gulf of Mexico ......................... 44

2:20 pm Decalf, Carole; Lock-Williams, Susan; Weber, Nathan; Cubanski, Mary; Yough, Charles; Etemadi, Mohamed; and Liro, Lou

Emplacement and Evolution of Salt in the Alaminos Canyon Protraction Area, Gulf of Mexico ................................................................................................................. 45

2:45 pm Bergeon, Thomas C. Seismic Imaging at Conger: Lessons Learned in Gulf of Mexico Subsalt Imaging ....... 46

3:10 pm Orange, Daniel L.; Williams, Mark; Hart, William; Thomson, Jim; Buddin, Tim; Angell, Michael M.; Brand, John R.; and Berger, William J. III

Slumps and Salt Tectonics at the Mad Dog and Atlantis Fields .................................... 47

3:35 pm Conference Ends

Poster Only

Dooley, Tim; McClay, Ken; Hempton, Mark; and Smit, DirkBasement Controls on Salt Tectonics: Results from Analog Modeling .......................... 48

Author Index............................................................................................................................... A-1

124th Annual Gulf Coast Section SEPM Foundation Bob F. Perkins Research Conference—2004

Salt Tectonics in the New Millennium: Navigating the Information Flood

Hudec, Michael R.Jackson, Martin P. A.Bureau of Economic GeologyJackson School of GeosciencesThe University of Texas at AustinUniversity Station, Box XAustin, Texas 78713U.S.A.e-mail: [email protected]

Abstract Successful hydrocarbon exploration has pro-

duced a surge of interest in salt basins in the last 15years. This attention, combined with advances in seis-mic data acquisition and processing, has revolutionizedour understanding of salt tectonics. However, thewealth of information is also a glut. Conventionalmechanisms for spreading knowledge through the geo-logical community, such as papers and presentations,are woefully inadequate for handling the volume ofinformation that now exists. It is difficult for interpret-ers newly assigned to salt basins to learn what theyneed to know, or for experienced salt interpreters tokeep up with advances in the field.

One solution to this problem is to try to mergethe current understanding of salt tectonics with moderninformation technology. We are constructing a digitalatlas of salt tectonics called The Salt Mine. The SaltMine is an HTML-based, interactive atlas of salt struc-tures and associated sediment geometries. Whencomplete, the atlas will contain hundreds of images ofsalt structures from around the world, together with

captions that discuss the processes illustrated. Allimages are grouped into structural styles, based on ageometric classification rather than on their mode oforigin, which is often contentious. Images include fieldexposures (outcrop views, geologic maps, aerial photo-graphs, and satellite images), seismic sections,geologic cross sections, conceptual sketches, and ani-mations. In addition, the atlas will showcase hundredsof the best examples from the Applied GeodynamicsLaboratory’s collection of physical and numericalmodels. Images in The Salt Mine can be located usingfive different methods: keyword search, geographiclocation, structural style, geometric classification tree,and a table of contents. In addition, three forms of helpare available: list of references, glossary of salt tecton-ics, and a user’s guide. The goals of this effort are toprovide novices in salt tectonics with a comprehensiveguide that assumes no previous knowledge and to offermore-experienced workers a ready source of analogsand alternative interpretations.


2 Program and Abstracts

On Integrating Salt Motion in Basin Modeling:A Hybrid Approach for Goal-Oriented Salt Flow

Mello, Ulisses T.IBM T. J Watson Research Center1101 Kitchawan RoadYorktown Heights, New York 10598 USAe-mail: [email protected]

Pereira, Sebastião C. A. de Mendonça, Jorge M.Rodrigues, José R. P.CENPES/Petrobras R&D CenterCidade Universitária, Quadra 7, Ilha do FundãoRio de Janeiro, RJ 21949-900 Brazil

AbstractIn this paper, we describe techniques to calculate

the internal flow from kinematic salt motions derivedfrom palinspastic reconstructions. The calculated inter-nal salt flow is integrated into the dynamic basinmodels. The internal salt flow is constrained by theimposed velocity field on the deforming boundaries,mass conservation, and the incompressibility conditionduring the salt deformation, yielding an optimal, physi-cally valid, kinematic motion that achieves the goalsspecified by the geologist. Stokes flow physics is usedto calculate the internal flow of a salt body induced bythe deformation of its surface. In the numerical solution

of basin models, an Arbitrarian Lagrangian-Eulerian(ALE) numerical scheme is used to couple the motionfield and compaction. This approach has the advantageof reproducing exactly the geologist’s reconstruction ofthe salt evolution, and the very complex salt shapesobserved in the field can be simulated without the diffi-culties normally associated with the solution ofdynamic viscous flow formulations. Therefore, thisapproach is an alternative to both the pure kinematicgeometric reconstruction and the traditional dynamicapproach.



Integrating Complementary Tools for Depth Imaging

Kapoor, S. JerryAlbertin, Uwe, K.WesternGeco3600 Briarpark Ave.Houston , Texas 77042e-mail: [email protected]

AbstractSeveral field examples of Kirchhoff depth imag-

ing, tomography, and wave-field extrapolation imagingare presented. These examples illustrate how compen-sation for anelastic attenuation, multiple attenuation,

tomography, and wave-field extrapolation can be usedin a complementary fashion to provide improved inter-pretation and imaging in areas of significant geologiccomplexity.



Numerical Modeling of Salt Tectonics on Passive Continental Margins: Preliminary Assessment of the Effects of Sediment Loading, Buoyancy,

Margin Tilt, and Isostasy

Ings, StevenDepartment of Earth SciencesDalhousie UniversityB3H 3J5 HalifaxCanadaemail: [email protected]

Beaumont, Christopher

Gemmer, Lykke*

Department of OceanographyDalhousie UniversityB3H 4J1 HalifaxCanada

*Current address: School of Earth SciencesThe University of LeedsLS2 9JT LeedsUnited Kingdom

Abstract

Salt tectonics in passive continental margin set-tings is investigated using a 2D vertical cross-sectionalfinite element numerical model of frictional-plasticsedimentary overburden overlying a linear viscous saltlayer. We present preliminary results concerning theeffects of sediment progradation over salt, buoyancydriven flow owing to density contrast between the sed-iment and salt, regional tilt of the salt layer, and localisostatic adjustment of the system. Sediment prograda-tion causes a differential load on the underlying salt,which can cause the system to become unstable, lead-ing to landward extension accommodated by seawarddistal contraction. Slow progradation (Vsp = 0.5 cm/yr)

of slightly aggrading sediments gives a diachronousevolution comprising four main phases: (1) initiationof salt channel flow and the formation of mini-basinsand associated diapirs; (2) onset of listric normalgrowth faulting and extension of the sedimentary over-burden; (3) large-scale evacuation of the salt,formation of pre-rafts and rafts, and inversion of themini-basins; and (4) formation of a contractionalallochthonous salt nappe that thrusts over the deposi-tional limit of the salt.

Buoyancy effects are investigated using modelswith density contrasts between overburden and sedi-

ment of 0, 100, and 400 kg/m3. Although the lateralflow driven by differential loading dominates in allcases, the form of the mini-basins, the overall saltevacuation, and style of diapirism are sensitive to

buoyancy forces, as the large density contrast producesthe most developed diapiric and mini-basin structures.

A regional seaward tilt of 0.2° (of the type thatmay be produced by thermal contraction of the riftedmargin) enhances and accelerates the overall seawardflow of the unstable slope leading to much earlier over-thrusting of the distal depositional limit of the salt. Theadded down-slope gravitational component also modi-fies the style of the mini-basins by enhancing thehorizontal channel flow by comparison with the verti-cal buoyancy driven flow. This reduces the apparentefficiency of diapirism.

Local isostatic adjustment, owing to overburdenand water loading, introduces a landward tilt of thesystem, thereby requiring salt to flow updip againstgravity during evacuation. Isostasy also changes theoverburden geometry and, therefore, modifies the sta-bility and flow velocity of the extending overburdenthrough the increased strength of the isostaticallythickened proximal overburden, and through the modi-fied differential pressure acting on the salt under thesecircumstances. The seaward flow of the unstable sloperegion is slower for the same overburden progradationvelocity, more salt remains beneath the shelf as rollersand pillows during evacuation, counter-regional faultsare more pronounced, and the allochthonous salt nappeprogressively climbs above the isostatically adjustingsediments as it overthrusts.



Geology of a Welded Diapir and Flanking Mini-Basins in the Flinders Ranges of South Australia

Dyson, Ian A.Salt Tectonics Australia ResearchP.O. Box 221Aldgate, SA 5154, Australiaemail: [email protected]

Rowan, Mark G.

Rowan Consulting Inc.

850 8th St.

Boulder, Colorado 80302, USA

AbstractThe Oladdie Diapir in the southern Flinders

Ranges of South Australia presents an exceptionalopportunity to examine salt withdrawal and mini-basindevelopment adjacent to diapirs. The diapir occurs onthe common limb of an anticline-syncline pair in theNackara arc of the Cambro-Ordovician Adelaide foldbelt. The post-diapiric contractional tilting and subse-quent unroofing have fully exposed a cross-sectionalview of the diapir and the flanking mini-basins fromthe autochthonous evaporite layer upward for approxi-mately 4 km. Both the autochthonous layer and thediapir comprise a caprock assemblage with a dolomiticsiltstone matrix surrounding exotic rafts, includingsandstone, that were depositionally interbedded withthe evaporite.

The base of the diapir is a triangular pedestalrooted in the autochthonous layer. Sandstone raftsoccur in recumbent folds within the pedestal and con-verge upward toward the pedestal apex. Higher, a steepweld associated with elongate sandstone rafts and rem-nant diapiric matrix connects the pedestal to a flaringdiapir at the top of the exposed section. Locally, a shale

sheath is preserved along the southern margin of theweld and pedestal.

During the Neoproterozoic, two salt-withdrawalmini-basins, having very different sedimentation ratesand facies, formed on either side of the Oladdie Diapir.Abnormally thick, transgressive units in the southernmini-basin form a monoclinal growth wedge that dipstoward the diapir and is down-dropped by over 1 kmrelative to the northern mini-basin. Varying develop-ment of near-diapir unconformities and debris flowsshow that the degree of halokinetic deformation on thetwo flanks also differs, suggesting variable bathymet-ric relief during diapir growth and mini-basinsubsidence.

The geometry of the welded diapir and its asym-metric mini-basins is analogous to the counterregional-style salt systems of the northern Gulf of Mexico andother basins. Thus, the Oladdie Diapir provides aunique opportunity to study salt-sediment interactionin a setting that has, until now, been observed only onsubsurface data.



New Insights to the Evolution and Mechanisms of Salt Tectonics in the Central European Basin System: An Integrated Modeling Study

from Northwest Germany

Mohr, MarkusKukla, Peter A.Urai, Janos L.Department of GeologyRWTH Aachen UniversityWüllnerstr. 2, 52056 AachenGermanye-mail: [email protected]

Bresser, Georg

Gaz de France Production Exploration Germany GmbH

Waldstr. 39, 49808 Lingen (Ems)

Germany

AbstractWe use an integrated approach of seismic inter-

pretation, sedimentary and structural analysis, andreconstruction to obtain a better understanding of thebasin evolution and salt tectonic mechanisms in theclassic Northwest German salt basin. Our data consistof prestack depth migrated 2D lines and 3D seismicvolumes, non-depth migrated seismic data, and welldata. The study area, located at the southwest marginof the Central European Basin, underwent a heteroge-neous evolution and a complex salt tectonic history.We propose that a gravity-gliding system in the Earlyto Middle Triassic caused rafting, initial salt move-ment, mini-basin growth at the basin margin, and saltpillow growth in the center of the basin. A second

phase of salt movement was initiated by the formationof a basement graben at the beginning of middle Keu-per time, triggering reactive diapirism, breakthrough,and extrusion of the salt. Subsequent downbuildingcontinued up to the Jurassic producing sedimentarywedges, salt flanges, and salt re-sedimentation. Wesuggest that the latest (reactivation) phase of salt riseby diapir shortening is due to Late Cretaceous to earlyTertiary basin inversion. In comparison to the passivemargin of the Gulf of Mexico basin, which is charac-terized by lateral progradation, the intra-continentalCentral European basin shows a polyphase salt tectonicevolution that occurred under different stress regimesand sedimentary environments.



Salt Intrusion: Time for a Comeback?

Hudec, Michael R.Bureau of Economic GeologyJackson School of GeosciencesThe University of Texas at AustinUniversity Station, Box X

Austin, Texas 78713-8924U.S.Ae-mail: [email protected]

AbstractEmplacement of allochthonous salt sheets by

intrusion, long rejected as a hypothesis in the Gulf ofMexico, may be an important process in the NorthwestGerman Basin. In that area, salt from the Permian Zech-stein and Rotliegend evaporites was intruded into theTriassic Röt salt during Late Cretaceous shortening,forming “salt wings” on the flanks of many salt struc-tures.

Structural restorations of cross sections overthree of these structures illustrate some of the pro-cesses involved in salt intrusion. In all cases, thepresence of separate detachments on the Zechstein andRöt salts played a key role in the style of deformationduring shortening. Two of the structures existed onlyas gentle Zechstein-cored salt anticlines prior to theLate Cretaceous. During shortening, the anticlineslocalized thrust faults that linked the Zechstein and Rötdetachment levels. The thrusts carried Zechstein salt

upward to intrude into the Röt. Sediments above theRöt salt deformed by a combination of thrusting anddetachment folding, with salt from the deeper Zech-stein level filling in the cores of the folds. The thirdstructure was a salt wall prior to the Late Cretaceous.Shortening squeezed the wall nearly shut. Part of thedisplaced salt extruded at the surface to form a saltsheet; the rest was intruded laterally to form a wing atRöt level.

Salt wings that were emplaced into the core ofdetachment folds can be interpreted as passive struc-tures that filled space during fold growth. However,this explanation does not account for salt wingsemplaced on the flanks of salt walls, which mayrequire a more active role for the salt. In either case, itappears that salt intrusion may be an important processin the formation of allochthonous sheets in basins hav-ing multiple salt layers.



Christmas Tree Diapirs and Development of Hydrocarbon Reservoirs: A Model from the Adelaide Geosyncline, South Australia

Dyson, Ian A.Salt Tectonics Australia ResearchPO Box 221Aldgate, SA 5154, Australiae-mail: [email protected]

AbstractChristmas tree diapirs in the Adelaide “Geosyn-

cline” of South Australia are characterized by lateraltongues of allochthonous breccia derived from anautochthonous level that contains evaporites and acaprock assemblage of blocks (or ‘rafts’) of non-evaporitic lithologies. These breccias may be attachedto a diapiric trunk (consisting of evaporites and brec-cias) that may be connected to the autochthonous level.This paper describes two prime examples that outcropat Pinda Springs and Wirrealpa Springs in the centralFlinders Ranges of South Australia.

The Christmas tree diapirs evolved from an ini-tially reactive triangular, or anvil-shaped, diapir andseparate two mini-basins of different accommodationpotential and often completely different sedimentaryfacies. An interpreted submarine salt glacier at Pindadiapir was extruded as an allochthonous salt tonguenearly 7 km long and 500 m thick. It overlies a major

disconformity close to the diapir and the step-like basesuggests aggradation and progradation within thetransgressive systems tract. At Wirrealpa diapir, multi-ple tongues are contained within some 50 high-frequency sequences of the main mini-basin wheredeposition was influenced by the high subsidence rate,coupled with high sediment supply. The distinction ismade between halokinetic sequences bounded byravinement surfaces and the high-frequency sequencesbounded by regressive surfaces of erosion. Bothsequence types can be arranged into progradational,aggradational, and retrogradational stacking patterns.The model for Christmas tree diapirs, based on outcropmapping, done as part of this study, suggests that anumber of potential hydrocarbon traps can be related todifferent stages in the evolution of these halokineticstructures.

mailto:e-mail: [email protected]


Recognition and Exploration Significance of Supra-Salt Stratal Carapaces

Hart, WilliamJaminski, JacekAlbertin, MartinBP America, Inc.501 WestLake Park BoulevardHouston, Texas 77079e-mail: [email protected]

AbstractThe term "carapace" has been informally used to

describe a variety of semi-conformable supra-saltstratal packages. We propose a concise genetic andgeomorphic definition and itemize the exploration ben-efits of carapace recognition. By specifying the term todenote condensed, sub-parallel strata originally depos-ited over bathymetrically raised salt domes, canopies,and sheets, we can define a genetic stratal family that isboth kinematically and sedimentologically distinctfrom adjacent and overlying basin-fill sequences.While stratal carapaces may be displaced into variedand extreme configurations within complex Gulf ofMexico salt systems, characteristic geomorphic traitsrender them recognizable on seismic data sets. Perchedatop allochthonous salt or remnant welds, Gulf ofMexico carapace packages range up to 5,000 feet inthickness and typically feature sub-parallel internalstrata. Basal strata are semi-conformable to the under-lying salt, while outer carapace boundaries may occuras lateral and vertical transitions to non-isopachous

strata, or as discrete unconformity surfaces and high-angle salt cutoffs. Carapace strata often deform assemi-rigid blocks, in contrast to flexed basin-fillsequences.

Numerous commercial and technical incentivesexist for identifying stratal carapaces: (1) they presentcompromised exploration targets, typically lackingextensive sand distributions and often assuming steepinclinations at mini-basin margins (2) they may belithologically prone to being geopressured and canpose substantial drilling challenges; (3) inclined cara-paces can form effective trapping surfaces foronlapping basin-fill reservoir facies; (4) shallow cara-paces may degrade seismic resolution of underlyingsubsalt objectives, while certain subsalt trap stylesincur the risk of containing deeper carapace strata; (5)semi-rigid carapace blocks enable novel restorations ofbowl-shaped canopy collapse basins; and (6) the cara-pace concept augments Gulf of Mexico ponded-slopefacies models.



Salt Sutures in Single- and Multi-Tiered Allochthons, Green Canyon and Walker Ridge Areas, Deep Water Gulf of Mexico

Liro, Louis M. Murillas, Joseba Villalobos, Lorenzo Gatenby, Glen Mathur, Vinod

Maxus (U.S.) Exploration Company1330 Lake Robbins DriveThe Woodlands, Texas 77380 U.S.A.e-mail: [email protected]

Abstract Improvements in 3D seismic data and depth

imaging of allochthonous salt bodies in the deep waterGulf of Mexico allow for detailed definition of individ-ual salt allochthons, and an understanding of theirnumber and distribution.

Single-tiered allochthons represent salt originat-ing directly from Mesozoic salt layers. The family ofsingle-tiered allochthons defines the present-day Sigs-bee Escarpment. Triangular notches along the base ofthe allochthonous salt surface commonly characterizesingle-tiered allochthons. The notches are locatedbetween demonstrable vertical salt feeder regions, andare interpreted to represent early lateral suture regionswith little associated sediment deformation. Perimetersutures are located between the tapering, leading edgeof the allochthon and its impingement with an adjacentallochthon. These sutures are most pronounced wherethe tapering leading edge of one allochthon impinges

upon the source feeder region of the second allochthon.

Multi-tiered allochthons emanate from deformedprecursors at deeper levels. They are typically rugosealong their top salt surface, resulting in seismic raypath distortion and the consequent loss of and/or a poorsubsalt image. Multi-tiered allochthons also displayabundant internal reflectors and complex suturing.

Extensive lateral sutures are observed both insingle-tiered and multi-tiered salt regions. Lateralsutures, in single-tiered allochthons, are associatedwith salt feeder regions and parallel or diverge slightlyaway from the base allochthon seismic event. Thesesutures are located in the lower third of the amalgam-ated salt body, suggesting an early origin. In multi-tiered allochthons, the lateral sutures are observed atany height within the allochthon and display less affin-ity to vertical salt sourcing regions.



A New Mechanism for Advance of Allochthonous Salt Sheets

Jackson, Martin P. A.Hudec, Michael R.Bureau of Economic GeologyJackson School of GeosciencesThe University of Texas at AustinUniversity Station, Box XAustin, Texas 78713U.S.Ae-mail: [email protected]

AbstractThe 500-km-long Sigsbee Escarpment overlies

the leading edge of a salt-canopy system in the north-ern Gulf of Mexico. The escarpment separates thelower slope from the abyssal plain. Bathymetric reliefof the escarpment ranges from 300 to 900 m, suggest-ing that the canopy is still advancing although it isalmost everywhere buried beneath a roof comprisinghundreds of meters of Pliocene–Holocene-age sedi-ments. Existence of such a roof means that the canopycannot be advancing by extrusion. Interpretations ofthe Sigsbee salt canopy have previously drawn atten-tion to thrusts that root into the leading edge of the salt.These thrusts are inferred to accommodate intrusiveadvance of the salt allochthon over the abyssal plain.Based on our interpretation of 3D pre-stack depth-migrated seismic data over a 48-km segment of theSigsbee Escarpment, we propose accretionary advanceas an additional hypothesis for salt sheet intrusion. Inmost of the study area, Pleistocene abyssal-plain sedi-

ments form an internally thrusted accretionary wedgein front of, and below, the leading edge of the salt can-opy. As the salt and its siliciclastic roof advance, newthrusts break progressively farther out into the unde-formed abyssal plain, increasing the cross-sectionalarea of the wedge. Because the footwall wedge con-tains synkinematic sediments, shortening decreasesupward, so the upper reflectors of the accretionarywedge are more continuous than the lower ones. Stack-ing of imbricate thrusts backfolds the base of the saltsheet. By this means, salt flats can become distorted toform apparent salt ramps. The Sigsbee accretionarywedge has features in common with convergent-mar-gin accretionary wedges, which are roughly ten timeswider and advance faster. Potential geohazards areposed by the existence of currently shortening, or for-merly shortened, accretionary wedges overridden byadvancing salt sheets.



Base of Salt Structure and Stratigraphy—Data and Models from Pompano Field, VK 989/990, Gulf of Mexico

Harrison, Holly Kuhmichel, LewHeppard, PhilMilkov, Alexei V.Turner, Joshua C.Greeley, Dave

BP America, Inc.501 WestLake Park BoulevardHouston, Texas 77079e-mail: [email protected]

Abstract The Pompano salt canopy has been penetrated by

six wells between 2001 and 2003 to test and developvarious subsalt and extra-salt plays. Data from thesewells provide insight into subsalt geologic models thatmay be applicable to other subsalt prospects in the Gulfof Mexico. The wells are aligned in a dip directionalong the length of the salt canopy from the upturnedsection (which onlaps the flank of the salt), to beneaththe salt, 5,600 feet back from the leading edge of thesalt. In addition, almost the entire Miocene section hasbeen tested below the salt. Pressure, dipmeter, andpaleontological data indicate a zone about 400 feetthick below the base of salt, roughly conformable withthe base of salt, and which terminates rapidly towardsthe leading edge of the salt canopy. These characteris-tic features are interpreted to be a shear or fault zoneimmediately below the base of salt.

The Pompano salt canopy is anomalous amongsalt sheets because permeable sands occur immediatelybeneath, and juxtaposed against, the base of salt in a

zone referred to as the ‘basal shear’ or ‘disturbed’zone. This provides a rare opportunity to measure thepore pressure within the zone, and to generate pressureprofiles below the salt.

Within the high-pressured section near the baseof salt, anomalous structural dips were encounteredwhich were generally parallel to the base of salt.Migrated, thermogenic petroleum fluids having vary-ing maturity and gas-oil ratio are found near the base ofsalt. Biostratigraphic data collected immediatelybeneath salt can indicate that the sequence is upright oroverturned and consistently older than the rock foundbelow, in addition to being fairly constant in thickness.The transition between the section adjacent to the saltand the country rock is abrupt and has all the attributesof a major fault. The section in the shear zone can beup to 1,000 feet structurally higher than the estimatedcut-off on the footwall. In light of these observations,the preferred subsalt model for Pompano is a base ofsalt shear zone.



Map Patterns of Rafted Blocks in Outcrops and Experimental Models

Le Calvez, Joël H. Schlumberger1700 Research Parkway College Station, Texas 77845e-mail: [email protected]

Vendeville, Bruno C.

Université des Sciences et Technologies de Lille

59655 Villeneuve d'Ascq Cedex

France

AbstractEarly evolutionary stages of salt-bearing margins

(e.g., South Atlantic or eastern Gulf of Mexico) ofteninclude one or more episodes of raft tectonism, duringwhich large overburden blocks, separated by normalfault zones, are translated basinward. Because bound-ary conditions prevailing during onset of deformationpartly control the trend and spacing of normal faults,they also determine the shape of rafted blocks in mapview. In addition, because boundary conditions in thedowndip part of the margin determine availableaccommodation space into which the rafted blocks aretranslated, they can influence the direction of raftmovement (parallel, convergent, or divergent).

The Canyonlands National Park area of Utah(Fig. 1) provided an excellent mesoscale field exampleof thin-skinned extension, where local boundary condi-

tions influenced the shape and translation direction ofrafted blocks. Rafting initiated when the ColoradoRiver incised the Cutler-Hermosa formations (overbur-den) down to the top of the mobile, evaporitic ParadoxFormation (source layer). The overburden spread grav-itationally toward the river valley, forming long rafts,that moved parallel (toward the valley), and that wereseparated by grabens whose traces are concave towardthe valley. Using physical models, we demonstrate thatfault curvature results from shear stresses between therafted area and fixed, lateral regions. In contrast,smaller areas bordering river meanders underwentdivergent spreading. Ironically, valley curvature thereled to formation of linear, rather than arcuate, faultsarranged in two orthogonal sets.



The Wilcox Raft: An Example of Extensional Raft Tectonics in South Texas, Northwestern Onshore Gulf of Mexico

Fiduk, Joseph C.Anderson, Lynn E.CGG Americas, Inc.16430 Park Ten PlaceHouston, Texas 77084-5056

e-mail: [email protected]

Rowan, Mark G.

Rowan Consulting, Inc.

850 8th Street

Boulder, Colorado 80302

AbstractExamination of 2D seismic data in South Texas

has identified what is now interpreted to be a large,rafted block of Eocene, Paleocene, and Cretaceousstrata, analogous to rafts identified in the KwanzaBasin of Angola. Preliminarily named the “Wilcoxraft” because of its association with the Wilcox depo-trough, it has been identified in the subsurfaceextending from Starr County on the Texas–Mexicanborder, northward over 200 kilometers into Live OakCounty, Texas. The actual extent of rafted materialmay extend farther to the north and/or south. The raft’sdetachment surface is interpreted to be at the base ofthe Jurassic Louann salt.

The Wilcox raft contains one primary blockmore than 150 kilometers long and 15 to greater than30 kilometers wide. The primary raft block may besegmented, and the entire rafted unit may include anumber of smaller branching arms, ramps, and offsetfault blocks. Various portions of the raft have downdipdisplacements from 5 to greater than 30 kilometers.The raft is bound on the west by expanded upper Wil-cox (early Eocene) strata and on the east by expandedQueen City (middle Eocene) strata. Other incompletelydetached blocks lie to the west of the raft across the

Wilcox depotrough. Raft geometries suggest that atleast one additional rafted block lies farther basinwardof the Wilcox raft, possibly beneath expanded Vicks-burg (early Oligocene) strata.

A proposal for rafting in this area of South Texasis not entirely new. Earlier modeling and restorationsacross the Wilcox depotrough have incorporated rafts.However, these models are predicated on large-scalesalt withdrawal and incorporate more than three kilo-meters (>10,000 feet) of autochthonous salt occupyingthe area of the Wilcox depotrough. We believe that amuch thinner autochthonous salt layer existed beneathSouth Texas. In other areas of the northern Gulf ofMexico, where thick autochthonous salt existed, saltstocks are abundant. Although a few salt structures doexist in South Texas, there are very few compared withother interior salt basins. Forward modeling suggeststhat large sedimentary structures in the Wilcox depo-trough, which can be misinterpreted as turtlestructures, are related strictly to deposition during raftextension and not salt withdrawal. The geometries canbe produced purely by extension on multiple detach-ments (Louann and lower Paleocene Midway shales)linked by ramps that dip both basinward and landward.



The Role of Halokinesis in Supra-Salt Fault Development: Insights from the North Sea

Banbury, NickUnderhill, JohnSchool of GeosciencesUniversity of EdinburghKings BuildingsWest Mains RoadEdinburghEH9 3JWUnited Kingdome-mail: [email protected]

Abstract Seismic mapping of the salt-influenced Late

Jurassic Shearwater fault system (central North Sea)has revealed that salt mobility has had fundamentalcontrol on the development of supra-salt faulting in thearea. The Shearwater fault system consists of four dis-tinct fault segments each of which increase indisplacement towards a salt diapir developed in a cen-tral area where the segments intersect. The evolution ofthe fault system is recorded by sediment geometries inLate Jurassic syn-rift sequences, which reveal that thesalt diapir and fault system evolved simultaneously

with a fundamental inter-relationship between saltmobility and the evolution of the fault system. Com-parisons of faulting in the Shearwater area with faultsdeveloped in the salt-free northern North Sea show thatsignificant differences exist in the nature of faultgeometries, footwall dips and fault related hangingwall depocenters. All of these variations can be attrib-uted directly to the influence of salt mobility.Consequently, caution should be used when applyingconventional models of fault development derivedfrom salt-free settings to evaporite basins.



Basement vs. Salt Tectonics and Salt-Sediment Interaction—Case Study of the Mesozoic Evolution of the Intracontinental Mid-Polish Trough

Krzywiec, PiotrPolish Geological Instituteul. Rakowiecka 400-975 WarsawPoland


AbstractThe Permian to Cretaceous Mid-Polish Trough

belonged to the system of epicontinental depositionalbasins of western and central Europe and was filled byseveral kilometers of siliciclastics and carbonates,including thick Zechstein (approximately Upper Per-mian) evaporites. The Mid-Polish Trough was invertedin Late Cretaceous–Palaeocene times, when its axialregion was strongly uplifted and eroded. The presenceof thick salt significantly influenced Mesozoic basinextension and inversion. Extensive seismic data isavailable which, in conjunction with deep research andexploration wells, enabled the construction of detailedtectono-stratigraphic models of the relationshipsbetween basement and cover tectonics as well as theinteraction between salt structures and surroundingdepositional systems. The apparent lack of majorextensional deformation within the post-salt Mesozoicinfill is responsible for several pulses of tectonic sub-sidence. These have been inferred from tectonic

modelling studies and are attributed to the basin-scalemechanical decoupling between the sub-salt (sub-Zechstein) basement and the post-salt Mesozoic sedi-mentary infill. During such decoupled evolution, majorfaulting was primarily restricted to the basement, andonly secondary faults and associated peripheral defor-mations developed within the post-salt sedimentarycover. In the central Mid-Polish Trough, because ofstrong basement extension, salt diapirs that partlyextruded onto the basin floor formed. The surroundingTriassic and Jurassic depositional systems werestrongly influenced by the combined effect of salt pil-low/diapir rise and basement extension. Detailedseismostratigraphic analysis of the cover patterns indi-cates the timing of major extensional andcompressional events and related formation of saltstructures. Results of seismic data interpretation con-form very well with published results of analogmodeling.



Regional Assessment of Salt Weld Timing, Campos Basin, Brazil

Roberts, Michael J.Metzgar, Craig R. Liu, JianchangChevronTexaco Energy Technology Company 4800 Fournace PlaceBellaire, Texas 77401


Lim, Siang J. Department of Geology and Geophysics

University of UtahSalt Lake City, Utah 84112

Abstract Pre-salt (Aptian) lacustrine shales are the pri-

mary source rocks that charge late Cretaceous andTertiary reservoirs in the petroliferous (15 billion bar-rels of oil recoverable) Campos Basin. As a result, anunderstanding of salt weld timing is a critical compo-nent in assessing charge risk and high-grading deep-water play fairways. The traditional method of assess-ing regional structural timing with isochron maps,although useful, often yields erroneous results whenweld timing is being ascertained. Mini-basins that havewelded and display onlap stratal geometry at their mar-gins may have the same isochron map pattern asactively subsiding basins which have growth wedgestratal architecture. Utilizing a regional grid of 2D seis-mic lines, we have developed a methodology whichidentifies salt weld timing by classifying the stratal

geometries of third order sequences within weldedmini-basins. These seismic facies accurately map theevolution of weld timing within each Campos mini-basin. A basin-wide “weld timing” map has been con-structed and compared to regional sedimentationpatterns and hydrocarbon charge modeling. At thelocal scale, the growth of individual welds can be com-pared with mini-basin structural geometries throughtime to assess drainage potential. We find that saltweld timing is positively correlated with regional sedi-ment isopach thickening but true weld timing andmini-basin evolution can only be understood by sys-tematically mapping stratal architecture.Understanding salt weld timing has profound implica-tions on basin modeling and future exploration riskassessment within the Campos and similar basins.



Do Salt Welds Seal?

Rowan, Mark G.Rowan Consulting, Inc.

850 8th St.Boulder, Colorado 80302e-mail: [email protected]

AbstractAn important question in the exploration of salt

basins is whether or not salt welds can seal hydrocar-bons in subweld traps. Any answer must start with theobservation that many supraweld traps throughout theworld are charged with hydrocarbons from subweldsource rocks, requiring migration through welds. How-ever, not all welds are the same, and this conceptualpaper examines various factors that may influence thesealing capacity of salt welds. The probability of weldseal is enhanced by: (1) the presence of remnantevaporite along the weld; (2) relatively impermeablelithologies across the weld; (3) subweld reservoirs thatare encased in shales rather than in contact with theweld; (4) the presence of clay gouge or smear gener-

ated during faulting; and (5) an original base-saltgeometry that creates divergent subsalt hydrocarbonmigration pathways. Another factor that must be con-sidered is the timing of overburden deformation withrespect to that of hydrocarbon generation andmigration.

Although weld seal is certainly a risk, traps thatinvoke weld seal should not be summarily discarded.Instead, each prospect should be evaluated separatelyin light of the factors presented here in order to derive abetter assessment of the inherent risk. In addition, theideas presented here need to be tested with observa-tions obtained from surface exposures and acombination of subsurface well and seismic data.



Hydrocarbon Migration and Accumulation Above Salt Domes—Risking of Prospects by the Use of Gas Chimneys

Heggland, RoarStatoil ASAN-4035 Stavanger Norwaye-mail: [email protected]

AbstractIn many cases, seismic data show indications of

shallow gas accumulations above salt domes. Faultscreated by the upward movement of the salt arebelieved to act as hydrocarbon migration pathways.This involves a risk of leakage from the deeper reser-voirs. Gas chimneys may provide additionalindications on the risk of leakage of hydrocarbons fromdeeper reservoirs.

To enable the mapping of gas chimneys in a con-sistent manner, a method for the detection of chimneysin post-stack 3D seismic data has been developed. Thisrecently developed method makes use of multiple seis-mic attributes and neural network technology. The

output, after chimney detection, is a 3D cube in whichhigh values have been assigned to samples insidechimneys and low values to the background, and fromwhich the shape and the spatial distribution of thechimneys can easily be visualized.

Gas chimneys have been observed above hydro-carbon-charged, as well as dry structures. However,the way chimneys appear in the two cases seems to bedifferent. Chimneys above dry structures coincide withfaults across the top of the structures. Chimneys abovehydrocarbon-charged structures are observed over awide area above each structure and are not coincidentwith a fault.



Geopressure Compartmentalization in Salt Basins:Their Assessment for Hydrocarbon Entrapments in the Gulf of Mexico

Shaker, Selim S.Geopressure Analysis Services (G.A.S.)1510 Village Green CourtHouston, Texas 77077e-mail: [email protected]

AbstractThe complex interaction between salt and sur-

rounding sediments makes risk assessment of aprospect or play concept a challenge. Geopressurecompartmentalization in the Gulf of Mexico Tertiary-Quaternary salt basins is created mainly by the princi-ple stresses resulting from interaction between thesediment load and tectonic movement of salt.

The unique petrophysical properties of salt con-tribute to changes in the structural setting and affect thesealing capacity and hydrocarbon retention capabilityof traps. The low density of salt may retard the sealingcapacity in subsalt sediments, while enhancing the sealcapacity in supra-salt sediments. Because salt is rela-tively impermeable, its contact with surroundingsediments forms a barrier to hydrocarbon movement.The integrity of the sealing interface is usuallyimpacted by the salt tectonic history.

The ductile nature of salt creates different formsof salt tectonics, such as diapirs, ridges, salt with-drawal basins, overhangs, canopies, etc., that have adirect impact on stress orientation.

Establishing the predicted pore pressure in theimpermeable beds (shale) compared to the measuredpressure in the reservoir facies (sands), plays an impor-tant role in assessing the entrapment and sealingcapacity of traps. In this study, wells are analyzed fromseveral different salt tectonic settings in the GardenBanks, Mississippi Canyon, and Green Canyon pro-traction areas (Fig. 1). While a great deal is knownabout salt body delineation from geological and geo-physical data, this paper addresses salt-relatedhydrocarbon traps from a geopressure standpoint.



Brine Vents on the Gulf of Mexico Slope: Hydrocarbons, Carbonate-Barite-Uranium Mineralization, Red Beds, and Life in an Extreme Environment

Sassen, Roger

Sweet, Stephen T.

DeFreitas, Debra A.

Eaker, Nancy L.Geochemical and Environmental Research Group (GERG)Texas A&M UniversityCollege Station, Texas 77845e-mail: [email protected]

Roberts, Harry H.Department of Oceanography and Coastal Studies Insti-tuteLouisiana State UniversityBaton Rouge, Louisiana 70803

Zhang, ChuanlunSavannah River Ecology Laboratory andMarine Sciences DepartmentUniversity of GeorgiaAiken, South Carolina 29802

AbstractEnormous volumes of middle Jurassic Louann

salt dissolve during migration of fluids from depth. Atthe seafloor, the result is vents, pools, and down-slopeflows of brine. At these locations, biogenic methane orC1-C5 thermogenic gases are present in high concen-

trations. New ∆14C measurements indicate a deepfossil source of this biogenic methane. However, gashydrate is not found at brine sites because high salinityretards the crystallization process. Microbial hydrocar-bon oxidation and sulfate reduction occur in brine andassociated sediment that drives massive precipitation

of authigenic carbonate rock depleted in 13C. Theauthigenic carbonate rock is often radioactive and hasdiagnostic barite-uranium mineralization.

Thick red beds occur as a consequence of mobili-zation of iron from the subsurface by brines. The flowof these brines over shallow, or exposed, salt in WalkerRidge in a water depth of 2,037 m has deposited rediron hydroxide layers up to 4.6 m thick. Iron comprises

24.1-24.6% of the sediment. Hematite, dolomite crys-tals, and uranium minerals are minor components of thered beds.

Methane-rich brines favor simple chemosyn-thetic communities of methane-oxidizing mussels andsulfide-oxidizing bacterial mats, decreasing biologicdiversity relative to nearby chemosynthetic communi-ties not affected by brines. Crude oil is altered bymicrobial oxidation, concentrating toxic aromatichydrocarbons in the brine environment along with ura-nium, radium, and toxic metals. Consequently, brine-related chemosynthetic communities appear to exist inthe most extreme environment for life on the seafloorof the Gulf of Mexico slope. The characteristics ofhydrocarbon-charged brine expulsion features arelikely to be preserved during deep burial, allowing dat-ing of major phases of hydrocarbon migration in thegeologic past.


The Role of Salt Dissolution in the Geologic, Hydrologic, and Diagenetic Evolution of the Northern Gulf of Mexico Sedimentary Basin

Hanor, Jeffrey S.Department of Geology and GeophysicsLouisiana State UniversityBaton Rouge, Louisiana 70803e-mail: [email protected]

Abstract Formation waters of the northern Gulf of Mexico

sedimentary basin (Gulf of Mexico) typically havesalinities significantly in excess of the fresh, brackish,or normal marine salinities that characterized the origi-nal depositional environments of most of the sedimentsin the basin. Although some of the excess salinity hasbeen inherited from brines formed by subaerial evapo-ration, much is the result of the subsurface dissolutionof halite. Subsurface dissolution has played an impor-tant role in the geologic, hydrologic, and diageneticevolution of the Gulf of Mexico. Salt dissolution hasreduced the volume of solid salt in the Gulf of Mexicoand may be a factor accounting for missing salt inlarge-scale reconstructions of the tectonic history ofthe Louisiana continental shelf and slope. Locally, lossof a cubic km, or more, of salt has been documentedfor some individual salt structures.

The formation of saline brines along with thehigh thermal conductivity of salt produces lateral andvertical fluid density differences that have the capacity

for generating vigorous fluid circulation around saltstructures and for long-distance fluid migration. Someof this density-driven fluid flow could be responsiblefor water-washing of hydrocarbons. On a regionalscale, thermohaline circulation has effectively decou-pled the regional meteoric and overpressured flowregimes in many areas of the onshore and coastal Gulfof Mexico. Spatial differences in formation watersalinity have proven useful in delineating reservoircontinuity and compartmentalization.

A large body of published analyses for Gulf ofMexico formation waters shows that as brines derivedfrom the dissolution of halite begin to evolve diagenet-ically, there is loss of dissolved Na and a gain indissolved K, Mg, Ca, and Sr as the fluids attempt toequilibrate with ambient silicate and carbonate mineralphases. The attainment of fluid-mineral equilibrationhas the potential for creating secondary porosity andprecipitating cements.



A Comparison of Salt Tectonic Subprovinces Beneath the Scotian Slope and Laurentian Fan

Shimeld, JohnGeological Survey of Canada (Atlantic)Natural Resources CanadaBedford Institute of OceanographyDartmouth, Nova Scotia B2Y 4A2 Canada email: [email protected]

(NOTE: Geological Survey of Canada Contribution No. 2004025)

AbstractA surge of exploration activity along the conti-

nental slopes offshore of Nova Scotia andNewfoundland has generated significant advances inthe understanding of the salt tectonics beneath theseregions. Although well control beyond the shelf breakis still sparse, extensive coverage by modern 2D seis-mic data permits definition of five tectono-stratigraphic subprovinces, each with a distinctive salt

deformation style related to regional basement mor-phology and first-order differences in sedimentation.The deformation styles range from halokinetic growthof passive diapirs sourced from a primary salt basin toextensive development of allochthonous canopies sea-ward of rapid progradation. Thin-skinned extensionaland contractional structures are evident throughout thestudy area.



A Comparison Between the Salt Basins of the Gulf of Mexico and the South Atlantic

Unternehr, Patrick de Clarens, PhilippeTOTALExploration & Production2 Place de la Coupole – La Défense 692078 Paris La Défense Cedex – Francee-mail: [email protected]

Abstract Two of the major petroleum-bearing salt basins

located on divergent margins are the Gulf of Mexicoand the South Atlantic. Even though investigationshave been going on for ‘decades,’ exploration is stillvery active, focusing particularly on deep-water Ter-tiary turbidite plays.

The geodynamic evolution of these margins con-trols the key parameters of salt tectonic evolution fromthe earliest stages in Jurassic-Cretaceous times to thepresent-day.

Some of the key parameters are compared anddiscussed as they relate to the regional geodynamiccontext:

• the size and shape of the initial, reconstructed,salt basins before the initiation of seafloor

spreading, including the presence of one or moresub-basins and their impact on the continuity ofthe salt décollement layer;

• the differences in the initial salt thickness and itsimpact on later ductile deformation;

• the control of the geometry of the basement; e.g.,ramp and flat, horst, etc. on salt tectonic zona-tions and deformation;

• the polyphase timing of the salt tectonics; i.e.,changes in the regional sliding/slope betweenearly and late deformations.

We conclude that the understanding of theregional evolution of these basins is the key to under-standing their salt tectonic evolution, which controlsthe primary parameters of petroleum systems.



Salt Tectonic Domains and Structural Provinces: Analogies Between the South Atlantic and the Gulf of Mexico

Mohriak, Webster U.Biassusi, A. S.Petróleo Brasileiro S.A. PetrobrasE&P—CORP—UN–EXP—GP—SSE20.035-900 Rio de Janeiro—RJ Brasil e-mail: [email protected]

Fernandez, B.

Paradigm, Rio de Janeiro—RJ

Brasil

Abstract Industry, regional deep-resolution seismic

reflection profiles along the shallow to ultra-deepwaterregions of the South Atlantic sedimentary basins allowthe interpretation of different salt tectonic compart-ments for the whole Aptian basin, which extends fromthe rift border towards the oceanic crustal limit. Geo-logical and geophysical interpretation, particularlyalong regional seismic transects in the eastern Brazil-ian and western African margins, reveals six major salttectonic provinces associated with gravitational slidingand spreading.

These tectonic provinces are characterized byparticular salt families that have counterpart structuralelements in the Gulf of Mexico, which shows betterdevelopment of Jurassic salt basins onland and muchthicker clastic input offshore in the Late Tertiary. Thetectonic domains in the offshore region (platform andin deep waters) are characterized by halokinetic struc-tures that developed huge salt diapirs, an extensionalprovince associated with turtle structures, roll-overs

and evacuation grabens, and particularly, by majordevelopment of allochthonous salt tongues.

Extensional elements predominate in the proxi-mal and intermediate provinces, whereascompressional features characterize basinward prov-inces near the continental—oceanic crustal boundary.Volcanic features, igneous intrusions, and wedges ofseaward-dipping reflectors characterize the transitionfrom rifted continental to oceanic crust. The deep-reso-lution seismic profiles also allow the identification ofautochthonous and allochthonous salt structures nearthe crustal boundary, forming bathymetric escarpmentsand salt nappes that extend towards the undeformedpost-salt sedimentary sequences overlying oceaniccrust.

Physical modelling experiments and seismic res-toration using balancing techniques can constrain theseismic interpretation. We also propose conceptualplays that have not been tested in the South Atlanticbut have been proved elsewhere, both in the Gulf ofMexico and in the North Sea.



Salt Tectonics of the Continent-Ocean Transition, Deep-Water Angola

Marton, GyorgyIndependent Consultant4804 Bellaire Blvd.Bellaire, Texas 77401e-mail: [email protected], GregChevronTexaco6001 Bollinger Canyon Rd.San Ramon, California 94583

Carpenter, Danielle

Cool, Thomas

ChevronTexaco

4800 Fournace Place

Bellaire, Texas 77401

AbstractThe Late Cretaceous to present salt-cored fold

and thrust belt at the edge of the Aptian salt basin, off-shore Angola, has been interpreted based on seismicand potential field data. Tectonic processes, kinematicsteps, and deformation styles are discussed and demon-strated using a series of regional cross sections andrestorations. Based on salt tectonic deformation style,the study area has been divided into a northern fold beltand a southern fold and thrust belt. Shortening alongthe measured section in the northern fold belt is on theorder of a few kilometers. In contrast, structural resto-ration demonstrates that to the south, in the fold andthrust belt, up to 12 km of compressional strain hasbeen absorbed by the Tertiary section.

Salt occurs at three levels in the frontal deforma-tion zone. At the deepest level, autochthonous saltpinches out against an outer high of oceanic basementat the western edge of the Angola salt basin. The sec-ond level comprises a deeply buried, regional saltcanopy, located at the leading edge of the salt provincein the northern part of the study area, which formed as

a salt glacier during the Late Cretaceous. Large-scale,compressional, salt-cored anticlines and active diapircomplexes have developed above this Cretaceous can-opy, and landward, above an inflated salt pillow inTertiary to present times. In the southern part of thestudy area, outboard of the Oligo-Miocene Congo Fandepocenter, and a zone of maximum extension, large-scale, salt-cored folds and thrusts developed aboveinterpreted oceanic crust. The third, and shallowest,level of salt is organized into a middle to late Miocenecanopy belt, observed just inboard of the frontalstructures.

In the northern fold and the southern fold andthrust belts large-scale structures initiated in the earlyTertiary and have continued to develop gradually.Large anticlines developed by downbuilding; i.e., bysalt injection into the fold core and contemporaneoussalt withdrawal from the adjacent synclines. Foldingand thrusting have been continuous up to the present,indicating a slow, but steady, deformation of the lead-ing edge of the salt province, offshore Angola.



Salt Tectonics and Sedimentation in the Offshore Majunga Basin, Madagascar

Tari, GaborCoterill, KatrinaMolnar, JimValasek, DaveWalters, GaryVanco Energy Company

Three Greenway Plaza, 12th FloorHouston, Texas 77046

Alvarez, YvesNova Sud25 rue Raveloary, Isoraka101 Antananarivo, Madagascar

Abstract The offshore Majunga basin of Madagascar

appears to be the largest salt basin in East Africa. It isthe previously very poorly known deep-water part ofthe Majunga that hosts a variety of salt features,including both autochthonous and allochthonous struc-tures which include toe-thrust anticlines, falling andrising diapirs, turtle structures, salt tongues/canopiesand withdrawal mini-basins beneath the slope. In themiddle of the salt basin, the salt edge displays a majorbasinward salient where the Early Jurassic syn-rift saltramped up through the Jurassic and Cretaceous strataforming a broad allochthonous salt nappe.

As only 2D seismic reflection data are availableover the Majunga salt basin, it provides only a sub-

regional scale example of the interaction between saltand sediments. One of the regional-scale aspects ofsalt/sediment interaction includes the relative impor-tance of updip sediment loading versus regional tiltingof the margin in the initiation of allochthonous salt tec-tonics. The uplift in the hinterland of the Majungabasin occurs during the mid-Cretaceous when the Sey-chelles/Indian continent rifted away from the easternside of Madagascar. It is suggested here that it was theregional basinward tilt that triggered the salt tectonics.Thus, the subsequent Late Cretaceous, accelerated sed-imentary influx only has enhanced the ongoing saltdeformation.


Salt Deformation, Magmatism, and Hydrocarbon Prospectivity in the Espirito Santo Basin, Offshore Brazil

Fiduk, Joseph C.

Brush, Eugene R.

Anderson, Lynn E.

CGG Americas, Inc.

16430 Park Ten Place

Houston, Texas 77084-5056


Gibbs, Peter B.Wealden Exploration, Ltd.The Dragon HouseSmarden, KentTN27 8NA, United KingdomRowan, Mark G.Rowan Consulting, Inc.

850 8th StreetBoulder, Colorado 80302

AbstractA combination of 3D pre-stack and post-stack

time-migrated seismic data was used to examine saltstructures, stratigraphy, and hydrocarbon potential inthe BES 2, 100, 200 and BMES 1, 2, and 9 blocks ofthe Espirito Santo Basin, Brazil. Salt structures displaya proximal to distal basinward transition from salt roll-ers, to vertical diapirs, to diapirs with overhangs andallochthonous tongues, and finally to salt canopies.The original autochthonous salt thickness increasesfollowing a similar proximal to distal basinwardgradient.

Deformation, driven by a combination of gravitygliding and gravity spreading, has been a relativelycontinuous process in the Espirito Santo Basin. Con-traction began early in the Albian and continuedunabated up to the present-day. However, individualstructures ceased movement at different times depend-ing on geometry, salt supply, and overburdenthickness.

A major thermal pulse affected the basin in theearly to middle Eocene, associated with emplacementof the volcanic Abrolhos Plateau. Both intrusive mag-mas and extrusive flows are interpreted to exist.

Intrusive dikes and sills display characteristic saucershapes in cross section, elliptical to circular shapes ontime slices, and cone shapes in 3D. Magmas appear tohave used existing salt structures and associated faultplanes as preferred pathways to reach shallower levels.Extrusive flows were identified only where seismiccharacter, clear stratal relationships, and direct ties tointrusive geometries allowed.

All the elements for excellent hydrocarbonpotential exist in the Espirito Santo Basin. The mainSyn-rift II source bed found in the Campos Basin existsacross the basin. Several other less documented sourceintervals also exist. Numerous contractional folds, tur-tle structures, and diapir-flank traps are present.Reservoir intervals exist in Albian carbonates, UpperCretaceous transgressive sands, and Cenozoic regres-sive sands. At least one deepwater hydrocarbon systemis operating, as evidenced by numerous shallow brightspots, gas chimneys, and a recent major deep-waterdiscovery. The presence of intrusive magmas mayadversely affect deeper source intervals in someplaces, but could locally bring immature source rocksinto the oil window.

[email protected]


Salt Evolution as a Control on Structural and Stratigraphic Systems: Northern Paradox Foreland Basin, Southeast Utah, USA

Trudgill, Bruce

Department of Geology and Geological Engineering

Colorado School of Mines

Golden, Colorado, 80401-1877

United States


Banbury, NickUnderhill, JohnSchool of GeoSciencesThe University of EdinburghThe King's Buildings, West Mains RoadEdinburgh EH9 3JG, ScotlandUnited Kingdom

AbstractThe Paradox Basin is an asymmetric foreland

basin, developed along the southwestern flank of theUncompahgre uplift in southeast Utah and southwestColorado, USA. This large basin (265km by 190km)developed during the middle Pennsylvanian-Permianancestral Rocky Mountain orogenic event. Salt struc-tures in the northern Paradox Basin form a variety ofstructural styles ranging from deeply buried salt pil-lows to complexly faulted diapirs and salt wallsexposed at the surface. Complex intra-formationalunconformities and rapid lateral stratigraphic faciesvariations indicate that salt structures were active overat least 75 Ma.

Analysis of field exposures, sub-surface well,and 2D seismic data across the northern part of thebasin reveals a complex relationship between crustalshortening, loading, creation of accommodation space,differential sedimentation, and salt movement. Saltflow through time across the northern part of the basinreflects the varying basin geometry and its response tosediment depositional systems. From the early stagesof salt movement in the upper Pennsylvanian, throughpassive growth of a series of large (up to 4 km high)salt walls, the dynamics of salt movement were astrong control on both structural development andstratigraphic facies architecture.



Compressional Salt Tectonics: Processes and Pitfalls

Szatmari, Peter Viana, Adriano R. Da Silveira, Desiderior P. Duarte, Cláudio S.L. de Freitas, João T.R. Gamboa, Luiz Antonio P.

Machado, Marco Antônio P. de Moraes, Marcos F.B. Carlotto, Marco Antônio Pereira, Sergio R. Gil, João A. Petróleo Brasileiro S.A.

AbstractSalt deposited over rift sequences along passive

margins flows basinward in response to thermal sub-sidence and non-uniform sediment loading. The flowresults in extensional tectonics in the salt and the over-lying sediments where the space is not constrained andin compressional tectonics where it is constrained. Saltwaves form as compression propagates inward fromthe borders of the laterally contracting body. Upslopeflow of the salt is particularly effective in creatingfolds having regular wavelength because of theincreasing resistance. Improved seismic resolution per-mits recognizing the complex internal structure of thefolds, whereas isolated 2D sections may be misleading.The resulting salt waves easily can be mistaken for dia-pirs in the conventional sense; their flanks may appeardiscordant when, in fact, they are not. Alternating

materials of different rheological properties greatlyenhance the formation of uniformly spaced waves orfolds. Apart from the dominant halite, the alternatingmaterial may consist of mostly mono- or polymineralicevaporite rocks such as anhydrite, carnallite, bischof-fite, or tachyhydrite, as well as alternating shale andsandstone/siltstone layers interlayered with, or overly-ing, the evaporites. Syndeformational sedimentationover the evaporites results in the formation of miniba-sins. The layers overlying the evaporites participate inthe folding, with upward decreasing amplitude, so thatdefinition of the upper boundary of the evaporitesequence on seismic sections is not always straightfor-ward. Seismic lines from Brazil’s Atlantic margin areused to illustrate these points.


Modes of Contractional Salt Tectonics in Angola Block 33, Lower Congo Basin, West Africa

Gottschalk, Richard R. Anderson, Arlene V.Walker, James D.ExxonMobil Exploration Company233 BenmarHouston, Texas, U.S.A. 77060 e-mail: [email protected]

Da Silva, Joaquim C.Sonangol DEXAv. 4 de Fevereiro 214

P.O. Box 1316Luanda, Angola

AbstractThe Lower Congo Basin is a gravitationally-

driven, linked extensional/contractional system,detaching on Aptian salt, in which updip extension iscompensated by downdip contraction and lateral flowof salt. Two spatially and temporally distinct phases ofdeformation are recognized in the Lower Congo Basin,one of Cretaceous age, and one of Oligocene to Recentage. Angola Block 33 is a deep-water block lyingentirely within the contractional domain of the Tertiarysystem. Recently acquired 3D seismic data providenew insights into the structural evolution of contrac-tional salt structures.

Several distinct structural domains are recog-nized on Block 33. (1) The northeastern portion of theblock is dominated by turtle anticlines, the principalstructural features in the Turtle Domain. (2) The East-ern Domain covers most of the eastern portion ofBlock 33, and is dominated by relatively simple, salt-cored folds associated with local subsidiary thrustfaults. North-northwest- to northwest-trending salt

walls are the predominant salt structures in the Turtleand Eastern domains. (3) The Western Domain, in con-trast to the relatively simple features in the eastern partof Block 33, is structurally complex, and exhibits avariety of features, including salt stocks, salt sheets,salt-cored anticlines, and thrust faults. Thrust faultsoccur in a variety of orientations, commonly emanat-ing from, and sometimes linking salt ascension zones.

Our analysis indicates that structures in Block 33evolved in two phases: (1) an Aptian to early(?) Oli-gocene phase that lead to the formation of turtles,diapirs, and salt pillows; and (2) a mid(?)-Oligocene toRecent phase of contraction. Because contraction wassuperimposed on a pre-existing system of salt struc-tures, mid(?) Oligocene to Recent folds and thrustfaults are strongly controlled by the geometry and ori-entation of older structures. Stratal patterns indicatethat early-formed diapirs evolved into salt glaciers atthe onset of contraction, and that contraction waslocally accommodated by lateral displacement of salt.



Insights from a Gravity-Driven Linked System inDeep-Water Lower Congo Basin, Gabon

Jackson, Martin P. A.Hudec, Michael R.Jennette, David C.Bureau of Economic GeologyJason School of GeosciencesThe University of Texas at AustinUniversity Station, Box XAustin, Texas 78713e-mail: [email protected]

AbstractDeep-water structures in southern Gabon are

among the best imaged in the world. Our 30-km-longstudy area in the Anton Marin–Astrid Marin blocksruns obliquely through the northern part of the CongoFan. The study area is entirely covered by high-quality3D seismic data. It spans the complex transitionbetween the landward extensional domain and the bas-inward contractional domain. Both domains detach onAptian salt. We use seismic sections and dip-correctedisochron maps to illustrate and analyze the followingprocesses.

Control of thrust location by precursor anti-clines and diapirs: a regular wavelength of the earlyAlbian gentle precursor anticlines nucleated linear,regularly spaced thrust faults; the location of precursorpassive diapirs caused some thrust faults to curve tointersect with the diapirs, linking them into the overallcontractional network, which includes lateral transferzones.

Thrusting that verged consistently seaward:most other salt-based thrust belts have less systematicvergence; we attribute the consistent vergence to thehigh frictional resistance of the salt detachment

because it had been thinned by expulsion of salt intodiapirs before thrusting began.

Landward propagation of thrusting: during thelate Cretaceous and Paleogene, thrusting propagatedupdip through the formerly translational domainbecause of the buttressing effect of older thrusts down-dip of the study area. In the study area, distal thrustsand diapirs were still shortening while more proximalthrusts began shortening.

Extrusion of salt sheets under compression: asthrusting culminated, the precursor passive diapirswere compressed to extrude salt; extrusion continueduntil the diapirs were finally squeezed shut, more orless coevally across the thrust belt in the study area.

Inversion of extensional salt structures: by theOligo-Miocene, the thrust belt had propagated land-ward into the formerly extensional domain; thus,diapirs and turtle structures were squeezed, old normalfaults were inverted as thrusts, new normal faultsformed orthogonally to older normal faults, and strike-slip faults linked older structures. The variable strikesof the old extensional or halokinetic structures causedthe strike of the inversion structures to be equallyvariable.



Salt Movement, Tectonic Events, and Structural Style in the Central Zagros Fold and Thrust Belt (Iran)

Letouzey, JeanInstitut Français du Pétrole92500 Rueil-MalmaisonFrancee-mail: [email protected]

Sherkati, ShahramN.I.O.C.Yaghma Allay-Jomhuri AvenueTeheranIran

AbstractStructural analysis of surface and subsurface

data in the Dezful Embayment, the northern Fars, andthe High Zagros provinces shows that the presence ofthe Eocambrian Hormuz and the Miocene Gasharansalt layers have a direct control on the structural style.Both are levels of major disharmony and decollementduring the Neogene Zagros folding.

There is some evidence that Hormuz salt domingstarted before the Neogene Zagros orogeny. Permo-Triassic Tethysian rifting along High Zagros north-west-southeast trends and Cretaceous-Paleogeneobduction and compressive events associated withbasement reactivation of north-south Arabian trendscould have initiated some episodic salt diapir activityin the Central Zagros province. However, in theabsence of high-quality, deep seismic imaging in mostof the Zagros fold zone, early Paleozoic or Hercyniansalt movements are not excluded.

The Hormuz complex is known from emergenthalite and anhydrite plugs in the Fars and High Zagrosareas. The emergence of Hormuz evaporite plugs isclosely associated with major thrusts parallel to thefold trend, such as the Dinar thrust. Plugs also occuralong tear faults or where space is created by pull-apartalong the north-south trending strike-slip faults. Thesefaults and the associated salt plugs are clearly related tothe Zagros folding event, even if they are sometimeslocated above reactivated paleo-structures. The analy-sis of the deformation of sandbox models using X-raytomography suggests that the initiation of thrust and

wrench faults is influenced by pre-existing salt domes(weak zones). The driving mechanism of Hormuzhalokinesis and extrusion was the squeezing of pre-existing salt domes. Local pull-apart and wrench faultdeflection probably also allowed for rapid rising of theevaporites.

In the Fars and High Zagros areas, the Hormuzsalt series played the role of a low friction, basal décol-lement level, and influenced fold style by freedevelopment of fore-thrusts and back-thrusts withoutany preferred vergence. The high competency con-trasts within the sedimentary pile favored thedevelopment of "fish tail" structures and caused axialshifting of anticlinal crests from surface to depth.

The Neogene sedimentary sequence begins withthe deposition of the evaporitic Gachsaran Formationabove the Asmari limestone reservoir. The lateralextent of this facies is restricted to the Dezful zone,marking the evolution of the area towards a fold beltand its associated flexural basin. Thickness variationsand early diapirism show that this syntectonic depositis contemporaneous with folding in this area. TheGasharan salt is a major level of décollement and dis-harmony in the north Dezful Embayment zone, southof the Mountain Front Fault. This interpretationimplies that the surface expression of the structuresdoes not reflect their geometry at depth. The Gachsa-ran evaporitic sequence also plays an important role insealing Asmari reservoirs.



Shale-Detached Deformation along the Texas Shelf: 3D Analyses, Recognition Criteria, and Development of

Duplex Structures in Extensional Settings

Palmes, Stephen L.Minerals Management Service1201 Elmwood Park BoulevardNew Orleans, Louisiana 70123e-mail: [email protected]

Abstract Detailed interpretations of 3D seismic data vol-

umes and analyses of derivative 2D kinematic modelsreveal complex stratigraphic and structural relation-ships that are interpreted as forming duplex structureswithin extensional settings. These structures developalong the Texas shelf in settings containing multiple lis-tric detachment faults soling at multiple levels.Laterally and vertically, the faults intersect and coa-lesce with one another in both map and cross-sectionalview. Younger, landward growth faults may detach atdeeper structural levels and can result in older, basin-ward detachment faults being folded into hanging wallstructures.

Conversely, younger detachments may sole intoolder detachment zones deforming the older fault andoverlying strata, forming hanging wall anticlines con-taining single, or multiple, folded faults. The resultingstructures can be termed “horses” or duplexes. Twodimensional, forward modeling of observed faultgeometries illustrates the structural development of

extensional duplexes in dip orientation, commonlyresulting in individual horses bounded by roof andfloor faults. In more complex settings, individualhorses may be excised, resulting in laterally and verti-cally stacked duplexes.

This paper documents the existence of exten-sional duplexes along the Texas shelf, provides criteriafor their recognition in strike, dip, and map view, pre-sents kinematic models for their structuraldevelopment, discusses the internal architecture ofduplexes, and identifies processes for the formation ofthe following structural features: horses, conformablechaotic zones, excised horses, and antiformal stacks. Afull understanding of the evolution of extensionalduplexes may help to assess trap, charge, sand, and res-ervoir risk. Applying this model to the structuralevolution of the Texas shelf may provide insights intothe structural style and deformational history of struc-tures associated with, and underlying, fault systemssuch as the Corsair and Clemente-Tomas.



Shale Tectonism in the Northern Port Isabel Fold Belt

Camerlo, RionMeyer, DavidDeepwater Business Unit ChevronTexacoHouston, Texas

Meltz, RobertGulf of Mexico Business Unit ChevronTexacoNew Orleans, Louisianae-mail: [email protected]

Abstract The northern extension of the Port Isabel Fold

Belt is a structurally complex, linked fault system thathas been significantly impacted by regional salt tec-tonism and shallow shale diapirism. Large-scalecapture of Miocene deposition updip of an Oligocene-age extensional zone, concurrent with evacuation ofsalt and ductile shale, has resulted in structural inver-sion and overprinting phases of deformation. Thestructural style of this zone is characterized by anupdip trend of deep Miocene basins flanked by down-dip large-scale rollover anticlines. Frio sediment-coredrollover anticlines are fringed on the downdip edges bythrusts, shale diapirs, or detachment folds. Inversionwithin this zone is expressed by faults having sense-of-motion reversal, rollover anticlines associated withbasinward vergent thrusts, pop-up structures, andshearing of large portions of the section.

The Anahuac shale is an important detachmentzone within the trend and is diapiric over much of thenorthern Port Isabel Fold Belt. The unit is very wellimaged because of its shallow position in the sectionand the high quality seismic data available over thearea, and thereby provides a rare opportunity to viewthe internal deformation of ductile diapiric shale. Theshale displays many characteristics similar to thedeformation style of salt including mini-basin forma-tion during early deposition, reactive diapirism of theshale layer triggered by regional extension, shale-coreddetachment fold formation, and contractional diapir-ism, as well as more unique characteristics such asclose juxtaposition of brittle and ductile behavior. Theductility of the Anahuac shale at shallow depth isunique in that it is not caused by overpressure, as isassumed of most diapiric shales.



Distribution, Nature and Origin of Mobile Mud Features Offshore Trinidad

Sullivan, SeanWood, Lesli J.Bureau of Economic GeologyJackson School of GeosciencesThe University of Texas at Austin1 University Station C1100Austin, Texas 78712-0254Austin, Texas 78713-8924e-mail: [email protected]

Mann, Paul Institute for GeophysicsJackson School of GeosciencesThe University of Texas at Austin4412 Spicewood Springs Rd. #600Austin, Texas 78759-8500 USA

AbstractThe formation of submarine mud volcanoes by

seafloor expulsion of deeply buried fine-grained sedi-ments, liquids, and gases into the water columncontrols deep-marine topography, sediment pathways,and biota distribution in eastern Trinidad. We use

approximately 8,000 km2 of 3D seismic data in waterdepths of -100 to -1,450 m to study the morphology ofover 161 mud volcanoes present in the study area. Avariety of morphologic features associated with mudintrusion are visible on, and well beneath, the seafloorand include hydrogeologically active mud ridges,cones, and mounds, as well as inactive buried mud vol-canoes and collapse features. Surface expressions ofthese features vary from 30m-deep sub-seafloordepressions to 150-m high cones, average slopes rangefrom <1° to 36°, and individual volcano deposits can

cover areas of as much as 10.5 km2. The mud volca-

noes of the study area belong to three differentprovinces: (1) a fault-focused province, (2) a mudridge province, or (3) a basin-fill province. These mudvolcano provinces are identified by variations in sur-face and subsurface mud intrusion morphology, pasteruptive flows, influence of nearby faulting, and thedepth of the mud mass feeding the mud volcano. Inaddition to the seismic data, 20 dropcores sampling 1meter of surface sediments above the extrusive mudfeatures have been obtained. These cores contain angu-lar lithic clasts and reworked fauna and flora thatoriginate from deeply buried strata. The presence ofauthigenic carbonates, abundant shell fragments, pre-served burrows, and replaced tubeworms indicate adense distribution of cold seep biota live in associationwith the fluids and gases that are emitted from mudvolcanoes.



Processes of Mud Volcanism and Shale Mobilization: A Structural, Thermal and Geochemical Approach in the

Barbados-Trinidad Compressional System

Deville, Eric Battani, AnneCallec, Yannick Guerlais, Sophie-HélèneMascle, AlainPrinzhofer, AlainSchmitz, JulienInstitut Français du Pétrole1-4, av. de Bois-Préau92 506 Rueil-Malmaison, Francee-mail: [email protected]

Lallemant, Siegfried

Université de Cergy-Pontoise,

av. du parc, 95031

Cergy Pontoise, France

Abstract

This paper illustrates the diversity of subsurfacesediment mobilization features in tectonically mobileregions in a shale-rich environment. In the studied areaof the southeastern Caribbean, new geophysical acqui-sition in Trinidad and Barbados spectacularly show thewidespread development of mud volcanoes and mas-sive sedimentary extrusions in the interference areabetween the southern part of the Barbados prism andthe active turbidite system of the Orinoco. Mud volca-noes are well developed along ramp anticlines, or ontop of sigmoid rises, which are oblique with respect tothe trends of the main folds of the accretionary wedge.The area also exhibits trends of structures correspond-ing to massive extrusions of well preserved turbiditeand hemipelagic sediments that cut the surroundingsediments. Some of these extrusion structures are com-plicated by the development of collapse structures,calderas, and superimposed mud volcanoes. On someactive mud volcanoes, heat flow measurements showhigh positive anomalies and bottom simulating reflec-tors that are shallower compared to the surroundingareas and show high fluxes of fluid expulsion. Themobilized sediments expelled by the mud volcanoes areliquefied argillaceous and sandy material from deephorizons, and various shallower formations pierced bythe mud conduits. Both in the Barbados prism and inTrinidad, the mud expelled is rich in thin, angular, andmechanically damaged quartz grains related to shearingand/or hydraulic fracturing processes. The exotic clastsand breccia result mostly from hydraulic fracturing. In

Trinidad, the gas phase is mainly deep thermogenicmethane associated with hydrocarbon generation atdepth.

This paper emphasizes that subsurface, clay-richformation mobilization notably differs from salt mobi-lization by the role taken by the fluid dynamics thatcontrol overpressured shale mobilization, and inducesediment liquefaction. Mud volcanism corresponds tofluid displacement, whereas massive sedimentaryextrusion corresponds to large movements of stratifiedsolid levels for which the deep cause could be theintrusion of mud plugs. Both are dynamic phenomenacontrolled by the development of overpressure atdepth, contributing to sediment mobilization by reduc-ing the strength within the overpressured layer. Theregime of the expulsion of the fluids varies accordingto cyclic phases. Low-frequency cycles, notably thecatastrophic events, are controlled by the dynamicdevelopment of overpressure. They could be related tothe fact that when high excess pore pressure occurs atdepth, hydraulic fracturing is responsible for openingthe fracture network favoring successive fluid releaseand cyclic pressure decrease. Such processes could beenhanced by a threshold effect when fluids are over-saturated in gas. In that case, massive degassing of alarge volume of dissolved gas at depth is possible,resulting in a sudden rise in fluid pressure and damageto the sealing properties of the sediments above gas-charged mud chambers.



Influence of Mobile Shales in the Creation of Successful Hydrocarbon Basins

Wood, Lesli J.

Bureau of Economic Geology

Jackson School of Geosciences

The University of Texas at Austin

University Station, Box X

Austin, Texas 78713-8924


Sullivan, Sean



1 University Station C1100Austin, Texas 78712-0254

Mann, Paul

Institute for Geophysics



4412 Spicewood Springs Rd. #600Austin, Texas 78759-8500 USA

Abstract

Shale mobilization (argillokinesis) is an impor-tant process in several major worldwide hydrocarbonbasins and in most cases is critical to their prospectiv-ity. The southern Gulf of Mexico, Niger offshore,Caspian Sea, northeastern Venezuela and Trinidad,Indonesia, and the Mackenzie Delta of northern Can-ada are all excellent examples of these argillokineticbasin types, where the effects and prospects associatedwith mobile shale systems can be examined in detail.Unlike salt, which will move and maintain movementunder very limited impulses, shale requires overpres-sure to become ductile. Shale may move from ductile,to plastic, to fluidized, and back to ductile, numeroustimes throughout its active life. Overpressure is typi-cally caused through some combination of burialcompaction, diagenesis of clays, kerogen maturation,and compressive tectonics. Shale’s tendency towardpulses of inflation and deflation results in dynamicstates of erosion, accumulation, and explosion associ-ated with mud volcanoes. The active fluid migrationnecessary to maintain these episodes forms vents forhydrocarbon migration from sometimes deeply buriedsource rocks to shallower reservoirs and traps, settingup the perfect prospective scenario. Traps associatedwith shale diapirs include detachment folding, diapirtoplap, diapir top drape or rollover rims, radial faults,tilted fault blocks, erosional truncation and associatedunconformity traps, lateral mini-anticlines, and down-built anticlinal flank traps.

Mobile shales are an important component of theoverall history of evolution in the Columbus and off-shore Orinoco sub-basins of the eastern East MaturinBasin, offshore northeastern South America. The areais located on the southeastern front of the modern dayBarbados accretionary prism. It is an area of activetranspressive tectonics, large-scale growth faulting,and enormous sedimentation from the Orinoco Delta.

Detachment growth folding is a prominent fea-ture in the shelf strata. Mobile shale features in thesemore proximal regions include shale walls, welds androllers. Large bi-directional and mono-directional roll-over anticlines form the major hydrocarbon fields inassociation with listric growth faults formed by gravitygliding over a deeply buried shale detachment surface.These fields trend parallel to, and are sourced by,deeply buried transpressive, northeast-to-southwesttrending faults. In the more distal, deeper waterregions, mobile shales are expressed in more plasticand fluidized eruption of mud volcano trains that paral-lel these same transpressive fault trends. Thickoverburden deposited by the Orinoco Delta inhibitssurface expression of mud mobilization in the proximalshelfal areas. In contrast, thinning overburden in distalregions allows faults to cut the seafloor and provideconduits for migration of deeper hydrocarbons to theseafloor surface.



Impact of Salt Movement on Fluvio-Lacustrine Stratigraphy and Facies Architecture: Late Triassic Chinle Formation, Northern Paradox Basin,

Southeast Utah, USA

Matthews, Wendy

Hampson, Gary

Department of Earth Science and Engineering

Imperial College London

South Kensington Campus, Exhibition Road

London SW7 2AZ

United Kingdom

e-mail: [email protected] and [email protected]

Trudgill, BruceDepartment of Geology and Geological EngineeringColorado School of MinesGolden, Colorado 80401-1877USA

Underhill, JohnSchool of GeoSciencesThe University of EdinburghThe King’s Buildings, West Main RoadEdinburgh EH9 3JGUnited Kingdom

Abstract Continental depositional systems influenced by

salt movement are characterized by rapid lateral andvertical facies changes that are difficult to predict at areservoir scale. This study presents preliminary obser-vations and interpretations of the Late Triassic ChinleFormation of the northern Paradox Basin, southeastUtah, USA, as a possible outcrop analog to subsurfacereservoirs due to its extensive 3D exposure across arange of salt structures that were active during its depo-sition. Salt movement commenced prior to ChinleFormation deposition, when active structures includedburied salt anticlines, salt walls exposed at surface, andsalt withdrawal minibasins.

In the northern Paradox Basin, regional subsid-ence and climate controls are locally overprinted by theimpact of halokinesis, which results in the break downof the regional Chinle Formation lithostratigraphy.Analysis of field exposures in this area allows the for-mation to be divided locally into five informal

lithostratigraphic units bounded by mappable surfaces.Depositional environments include lacustrine, fluvial,and aeolian. The local stratigraphic framework allowssalt-sediment interaction to be recognized by localized(km-scale) stratigraphic thickness variations, angularstratal relationships, and changes in facies architecture.Areas of active salt evacuation (e.g., rim synclines andsalt-withdrawal minibasins) are characterized byexpanded stratigraphic thickness, preferential develop-ment and preservation of fine-grained floodplain andlacustrine deposits, and convergent or deflected pale-ocurrents. Salt walls that were exposed at the surfaceare characterized by the absence of strata, and theoccurrence of rotational unconformities; they also havedeflected paleocurrents and abundant reworked sedi-ment into directly adjacent areas. Buried saltstructures, active at depth, are also associated with sub-tle thickness variations and sediment slumping downtheir paleoslopes.




3D Structural Restoration of Ponded-Basin Turbidite Reservoirs in aLinked Extensional-Compressional Salt Basin,

Holstein Field, Deep-Water Gulf of Mexico

Byrd, TomBP Gulf of Mexico Deep Water Development200 Westlake Park Blvd.Houston, Texas 77079, USAMeisling, KristianBP Upstream Technology501 Westlake Park Blvd.Houston, Texas 77079, USAJaffey, NoahMidland Valley Exploration Ltd14 Park CircusGlasgow, G3 6AX, UK

Vines, JohnBP Upstream Technology501 Westlake Park Blvd.Houston, Texas 77079, USABuddin, TimMidland Valley Exploration Ltd.1767 Denver West Marriott BlvdGolden, Colorado 80401, USAEkstrand, EricBP Gulf of Mexico Deep Water Development200 Westlake Park Blvd.Houston, Texas 77079, USA

AbstractThe Holstein Field comprises multiple, ponded-

basin turbidite reservoirs deposited in a mini-basinabove allochthonous salt in southern Green Canyon,Gulf of Mexico. The mini-basin formed above a con-densed shale section detached by gravity sliding fromthe underlying salt and bound by a linked extensional-compressional system of faults (updip to downdip) andhas oblique- and strike-slip deformation on the mar-gins. This deformation had direct control on thesediment entry and exit points. Associated synclinaland anticlinal structures influenced seafloor topogra-phy, depositional patterns and facies. The evolution ofthis structural system continued with punctuated epi-sodes of fill-and-spill turbidite deposition. Althoughseveral successive reservoir intervals filled pondedrelief and shared common characteristics, the grossbasin system demonstrated an offset-stacking patternonlapping updip, normal to sediment input direction.

High-resolution seismic and early well controlresolve critical details of reservoir architecture fordevelopment planning, but steep structures and multi-ple episodes of faulting on the reservoir marginslocally degrade seismic imaging and introduce geomet-ric complications to isopach mapping. A 3D structuralrestoration was applied to remove post-depositionalstructural overprint and to restore sequentially reser-voir stratal geometries for facies mapping. Therestoration provides a three-dimensional template ofaccommodation space at reservoir scale. A simpledown-dip migration algorithm was used to model sedi-ment dispersal within this template enabling predictionof vertical and spatial facies distributions, improvingon existing datasets. The restoration investigatedevolving topographic controls on deposition illustrat-ing a detailed 4D story and provided quantitativeestimates of basin relief for more rigorous sedimentmodeling


Interpreted Shallow and Deep-Water Depositional Systems of the Beltana Mini-Basin in the Northern Flinders Ranges, South Australia

Dyson, Ian A.Salt Tectonics Australia ResearchP.O. Box 221Aldgate, SA 5154Australiae-mail: [email protected]

Abstract

Salt-sediment interaction in the Adelaide ‘Geo-syncline’ of South Australia has had a pronouncedinfluence on deposition of the Late Precambrian toEarly Cambrian succession that is well exposed in thenorthern Flinders Ranges. In this area, mini-basins areeffectively windows into the salt withdrawal-relatedsedimentary section. Depositional systems of mini-basins and associated syn-depositional synclines arecharacterized by interpreted shallow and deep-waterfacies. In this paper, shallow-water facies/sedimentsare defined as those deposited above storm wave base,while deep-water facies/deposits are classified as thosedeposited below storm wave base.

The mini-basins are interpreted to haveformed by either a combination of salt withdrawaland salt dissolution (Breaden Hill Mini-basin), orsalt withdrawal (Beltana Mini-basin). Salt dissolu-tion troughs are characterized by marinesediments interpreted to have been deposited inshallow water on the floor of the mini-basin. Incontrast, interpreted lowstand, basin floor andslope fans occupy the basal fill of salt withdrawaltroughs.

The Beltana mini-basin, the model discussed inthis paper, is a classic example of an interpreted saltwithdrawal mini-basin. An angular unconformity over-lies slumped, lowstand facies of the mini-basin andmarks the transition to regressive sedimentation.Regressive sedimentation of the highstand systemstract in this model is followed by pronounced subsid-ence and abundant sediment supply, resulting in alocalized 2- to 5-fold increase in the depositional thick-ness of tidal marine facies. Stacking patterns suggest

these facies can be assigned to the aggradational wedgesystems tract that onlaps the rising flanks of the mini-basin. A major angular unconformity caps thissequence, marking incision of sea floor valleys that aresubsequently infilled with shoreface facies. Continuedsubsidence results in the formation of a broader syn-depositional syncline above the mini-basin. A subma-rine canyon directly overlies the axis of the main mini-basin fill. It can be traced updip to a location where adeep-water dolostone overlies a surface of terrigenoussediment starvation.

Salt withdrawal and sediment loading combinedto drop the floor of the mini-basin, and as sediments ofthe mini-basin flanks were uplifted and rotated, the rel-ative fall in base level resulted in canyon incision. Assubsidence continued, over-steepening of the basinmargin resulted in slump and debris flow faciesderived from the wall of the mini-basin or the subma-rine canyon. These deposits were contemporaneouswith, or closely followed by, deposition of a channel-ized, clast-supported breccia. Submarine canyons inmini-basins and syn-depositional synclines had noshallow-water, updip equivalent. Instead, the deepmarine sediments, subsequently deposited, wereassigned to the forced transgressive systems tract. Sed-imentation was generally transgressive, but waspunctuated by unconformity-based debris flows andchannel-fill breccias.

The Beltana mini-basin model predicts anumber of stratigraphic, structural and combina-tion hydrocarbon trap types that can be tied to thesequential formation of major unconformitieswithin the mini-basin.



Bathymetric Control on Paleocene Gravity Flows Around Salt Domes in the Central Graben, North Sea

Davison, IanEarthmoves Ltd.Chartley House38-42 Upper Park Road CamberleyGU15 2EF, United Kingdom e-mail: [email protected]

AbstractNorth Sea Central Graben salt diapirs grew by

both passive downbuilding and active compressionalreactivation during deposition of large Paleocene ageturbidite fans derived from the uplifted Scottish plat-form. Once downbuilding diapirs were buried by morethan approximately 200 m of overburden, includingsome Late Cretaceous chalk, very little bathymetricrelief (<20 m) was present over the salt domes, and tur-bidites could flow across the crests of the salt diapirs.Diapirs having less, or no, overburden present duringthe Paleocene created more bathymetric relief (rangingbetween approximately 100 to 300 m), which divertedturbidite flows around the diapirs. Consequently, sand-stones are absent on the crest of these salt domes, andhigh angle onlap reflectors are present on the diapirflanks.

The turbidite sandstones close to the diapirsshow large amounts of slumping and soft sediment

deformation where the paleo-topographic relief washigh during deposition (e.g., South Pierce, Merganserdiapirs). This can have a slightly detrimental effect onoil recovery, but apparently not productivity, if theaffected sequence contains shales.

Some diapirs (e.g. Jenny and Kyle, Fig. 1) areflanked by Paleocene debris flows containing lithifiedchalk fragments and occasionally reworked Zechsteinevaporites indicating that the salt diapirs were emer-gent, or had high local sea bed relief. These flows canconstitute high quality reservoirs due to the largeamount of inter-clast porosity and later fracturing.

This study indicates the importance of analyzingthe thickness and nature of the overburden presentabove salt crests, and the sediment onlap patterns,when turbidite deposition took place. These observa-tions can be useful in predicting the presence, orabsence, of turbidites over the crests of salt diapirs.



Summary of Halokinetic Sequence Characteristics from Outcrop Studies of La Popa Salt Basin, Northeastern Mexico

Giles, Katherine A.Lawton, Timothy F.Institute of Tectonic StudiesNew Mexico State UniversityLas Cruces, New Mexico 88001-8003e-mail: [email protected]

Rowan, Mark G.Rowan Consulting, Inc.

850 8th Street

Boulder, Colorado 80302

USA

AbstractLa Popa salt basin of northeastern Mexico con-

tains exceptional exposures of salt stocks, saltwithdrawal basins, and secondary salt welds, so thatthe scale and geometry of structural and stratigraphicfeatures created by salt movement can be examined inboth plan view and cross section. Cretaceous throughPaleogene strata exposed adjacent to diapiric structuresin La Popa Basin are arranged into halokineticsequences, which display onlap and thinning towardthe diapirs and stratal geometries indicative of syn-depositional diapiric growth. Within the shelf deposi-

tional environment in La Popa basin, halokineticsequences can be split into two end-member types(Type A and Type B) that differ in depositional facies,maximum degree of internal folding, amount of faultreactivation on unconformities, overall sedimentationrate, and distance of halokinetic sequence terminationfrom the salt/sediment interface. The differences inattributes of these two end-member types of haloki-netic sequences have important implications forreservoir quality, geometry, and continuity.



Petroleum Systems Analysis and Comparison of Inversion Structures (Turtles and Half Turtles), Eastern Salt Canopy Trend:

Deepwater Gulf of Mexico

Eisenberg, Richard A. Combs, Wes Johnson, Matthew Eastham, Kevin ChevronTexaco

AbstractSince the initial drilling at Metallica and subse-

quent discoveries at Thunder Horse and Thunder HorseNorth there has been a significant increase in wildcatdrilling activity in the Eastern Salt Canopy Trend ofthe deep water Gulf of Mexico. An additional discov-ery at Blind Faith and a series of dry-holes/non-commercial discoveries in the trend has shown, how-ever, that the petroleum system characterizing this playtype is more complex then previously thought. To date,eleven prospects targeting deep Miocene reservoirs ininversion structures have been drilled in the EasternSalt Canopy Trend resulting in a geological successrate of 0.55. Our understanding of these petroleum sys-tems and our ability to accurately assess the geologicalrisk of prospects of this play type has evolved rapidlyover the past 5 years as a result of deeper exploratorydrilling and public availability of data from thesewells. Regional and prospect scale structural mappingof proprietary pre-stack depth migrated seismic data,analysis of well logs, and interpretation of the strati-graphic relationships between inverted mini-basinsprovide the framework for this comprehensive sum-mary and comparison of the petroleum systemscharacterizing this play type.

Structural and stratigraphic analysis of theMiocene inverted mini-basins in the Eastern Salt Can-opy Trend reveals significant patterns with respect toreservoir, hydrocarbon charge and focus, seal andstructural geometry. Discoveries in the trend are foundwithin aerially restricted 4-way closures produced bystructural inversion of primary depocenters and withinrelated 3-way closures along the margins of the mini-basins against the allochthonous salt canopy. Structuralfeatures beneath and along trend to the Miocene inver-sion structures provides necessary migration conduitsand hydrocarbon focus for these structural highs. Vari-ability in reservoir quality with depth is related tocomplex burial/diagenetic histories and the proximityto thick salt. Structural inversion in the middleMiocene subsequent to significant periods of lowstandcreates the laterally extensive top seal for these hydro-carbon systems during ensuing transgressive periods.Although our understanding of these petroleum sys-tems has come a long way since the first hydrocarbondiscovery at Thunder Horse, a large degree of geologi-cal uncertainty still exists. The ability to adapt to theseevolving challenges and integrate new data as itbecomes available will ultimately determine the long-term exploration success within this trend.


Emplacement and Evolution of Salt in the Alaminos CanyonProtraction Area, Gulf of Mexico

Decalf, CaroleLock-Williams, SusanWeber, NathanCubanski, MaryYough, CharlesEtemadi, MohamedVeritas Exploration Services Division10300 Town Park DriveHouston, Texas 77072e-mail: [email protected]

Liro, Lou

Maxus Exploration Company

1330 Lake Robbins Drive

The Woodlands, Texas 77380

AbstractThe Gulf of Mexico is one of the most prolific

and challenging basins in the world to explore in forhydrocarbons in deep-water. Success in deep-waterexploration is contingent on knowledge of depositionalsystems, as well as salt tectonic geology. Over thestudy area, which is located in the Alaminos Canyonprotraction area, 3D pre-stack depth imaging of seis-mic data provides definition of salt emplacement andevolutionary history. In this region, shallow allochtho-nous salt may be sourced directly from the Jurassic

Louann layer. Emplacement of this salt occurred alonga series of low-angle and high-angle surfaces towardthe Sigsbee Escarpment. This basinward moving saltevolved as a salt nappe system. The salt nappe progres-sively advanced upsection and basinward over longdistances from its feeders. The quality of the resultingdepth migrated image allows description of prospecttypes in the subsalt section. It also allows for the defi-nition of the northeast termination of the Perdido FoldBelt and Sigsbee Escarpment in the study area.



Seismic Imaging at Conger: Lessons Learned in Gulf of Mexico Subsalt Imaging

Bergeon, Thomas C. Shell Offshore Inc. 701 Poydras St.New Orleans, Louisiana 70139(504) 728-6480e-mail: [email protected]

AbstractThe Conger Field is a significant subsalt discov-

ery located in the northeastern portion of GardenBanks. Production from four subsea wells has beensteady and is very prolific since first production startedin November 2000. (Conger was discovered in late1997.) Conger is partially beneath salt. Reservoirs con-sist of multiple, geopressured, high-quality turbiditesandstones at depths ranging from 19,500 to 21,000feet. These reservoir sandstones exhibit acoustic

impedance contrasts that give rise to distinct seismicamplitude anomalies when hydrocarbon filled. How-ever, despite the strong impedance contrasts, overlyingsalt distorts the seismic image significantly, and thesubsurface evaluation heavily relies on the well dataand geologic analogs. To-date, production at Congerhas been excellent, confirming the geologic model forthe field; i.e., laterally continuous sandstone reservoirswith minimal faulting.



Slumps and Salt Tectonics at the Mad Dog and Atlantis Fields

Orange, Daniel L.AOA Geophysics Inc.Marine Geoscience Division7532 Sandholdt Road, 2nd FloorMoss Landing, California 95039e-mail: [email protected]

Williams, Mark Hart, William Thomson, Jim BP America Inc.501 Westlake Park BoulevardHouston, Texas 77079

Buddin, TimMidland Valley Exploration Ltd.1767 Denver West Marriott Blvd.Golden, Colorado 80401

Angell, Michael M.William Lettis & Associates999 Anderson Drive, Suite 120San Rafael, California 94901

Brand, John R. Berger, William J. IIIGeoscience Earth & Marine Services10615 Shadow Wood Dr, Suite 200Houston, Texas 77043

AbstractThe interaction of salt and sediment at the Sigs-

bee Escarpment controls the geohazard environment atthe Mad Dog and Atlantis fields development areas.Understanding the role of salt tectonics, and its controlof the shallow geologic setting of the Sigsbee Escarp-ment, is critical to evaluating the shallow geohazardsof these fields. Exploration 3D, high-resolution 2D and3D seismic data, autonomous underwater vehicle data(bathymetry, side-scan, sub-bottom profiling), pistoncores, boreholes, and remotely operated vehicle obser-vations all provide information regarding the seafloorand subsurface geologic setting, and, in particular, therole that salt tectonics plays in creating, or modifying,the observed geologic features.

On the seafloor, bathymetric data show distinctdomains characterized by contrasting seafloor texturesincluding dramatic differences in the style of seafloorslumping. We show that these differences are due to acombination of salt morphology, supra-salt stratigra-phy, and faulting.

There are two primary modes of slope failure onthe escarpment face: shallow-seated, small-scaleslumping, and deeper-seated, amphitheater-shapedfailures. We differentiate among fault systems andslope failures of different origin and relate these differ-ences to seafloor geomorphic provinces and variationin the geometry and movement history of salt.

Both normal faults in the supra-salt section, andseaward dipping beds above the frontal salt monocline,can provide pre-existing and preferential failure planesfor slumping at the escarpment front. These dip slopeconditions control the slumping in the shallow-seatedslope failure portions of the escarpment at both thesouthwest Mad Dog and northeast Atlantis field areas.Deeper seated slumps may be related to retrogressivefailure facilitated by internal overpressures.

The unprecedented detail of the data sets in theMad Dog and Atlantis field areas allows a detailedkinematic model to be developed for the SigsbeeEscarpment, and an improved assessment of the geo-hazards.



Basement Controls on Salt Tectonics: Results from Analog Modeling

Dooley, TimBureau of Economic GeologyJackson School of GeosciencesThe University of Texas at AustinUniversity Station, Box XAustin, Texas 78713USAe-mail: [email protected]

McClay, KenFault Dynamics Research GroupRoyal Holloway University of LondonEgham, Surrey TW20 0EXUK

Hempton, MarkSmit, DirkShell UK Ltd.1 Altens Farm RoadNigg, Aberdeen AB12 3FYUK

AbstractPhysical models of salt tectonics related to thick-

skinned extension have been largely confined to 2Dstudies. An experimental program, utilizing siliconepolymer and silica sand/ceramic beads as ductile andbrittle analogs respectively, was designed to investi-gate the 3D relationships between salt diapirs and acomplex, bimodal, basement fault system during majorextension and minor inversion events.

During extension, intersection points in the base-ment fault system generate complex, single, 2-way, or3-way flap structures in the overburden localizing coverdeformation and footwall diapiric activity on the riftmargins. Flap structures and associated diapirs arelocated adjacent to, but diagonally inboard of, the base-ment intersection points and consist of convex-to-the-hanging wall fault segments that are gradually breachedby rising polymer with increasing extension. Major dia-pirs that attain passive status accommodate much of the

continued basement extension through downbuildingprocesses, resulting in heavily segmented basin mar-gins. Intra-basin horst systems develop inward-dippinggrabens cored by a major salt wall during initial exten-sion. Axial flow along this structure feeds growingdiapirs. Grounding of the brittle overburden results insource cut-off and deflation of the salt wall due to con-tinued expansion of the cover graben by extensionalprocesses.

During subsequent inversion major diapirs arereactivated, exhibiting rapid active rise through theoverburden, suggesting that buoyancy forces associ-ated with diapirs play a major role in their reaction tosubsequent tectonic stresses. Diapir crests andentrained salt bodies are nucleation sites for the devel-opment of high-level, commonly rootless, brittlereverse faults.


A-124th Annual Gulf Coast Section SEPM Foundation Bob F. Perkins Research Conference—2004

Author Index

AAlbertin, Martin 9Albertin, Uwe, K. 3Alvarez, Yves 27Anderson, Arlene V. 31Anderson, Lynn E. 14, 28Angell, Michael M. 47

BBanbury, Nick 15Battani, Anne 37Beaumont, Christopher 4Bergeon, Thomas C. 46Berger, William J. III 47Biassusi, A. S. 25Brand, John R. 47Bresser, Georg 6Brush, Eugene R. 28Buddin, Tim 40, 47Byrd, Tom 40

CCallec, Yannick 37Camerlo, Rion 35Carlotto, Marco Antônio 30Combs, Wes 44Cool, Thomas 26Coterill, Katrina 27Cubanski, Mary 45

DDa Silva, Joaquim C. 31Da Silveira, Desiderior P. 30Davison, Ian 42de Clarens, Philippe 24de Freitas, João T.R. 30de Moraes, Marcos F.B. 30Decalf, Carole 45Deville, Eric 37

Dooley, Tim 48Duarte, Cláudio S.L. 30Dyson, Ian A. 5, 8, 41

EEastham, Kevin 44Eisenberg, Richard A. 44Ekstrand, Eric 40Etemadi, Mohamed 45

FFernandez, B. 25Fiduk, Joseph C. 14, 28

GGamboa, Luiz Antonio P. 30Gatenby, Glen 10Gemmer, Lykke 4Gibbs, Peter B. 28Gil, João A. 30Giles, Katherine A. 43Gottschalk, Richard R. 31Greeley, Dave 12Guerlais, Sophie-Hélène 37

HHampson, Gary 39Hanor, Jeffrey S. 22Harrison, Holly 12Hart, William 9, 47Heggland, Roar 19Hempton, Mark 48Heppard, Phil 12Hudec, Michael R. 1, 7, 11, 32

IIngs, Steven 4

A-2 Author Index

J

Jackson, Martin P. A. 1, 11, 32Jaffey, Noah 40Jaminski, Jacek 9Jennette, David C. 32Johnson, Matthew 44

K

Kapoor, S. Jerry 3Krzywiec, Piotr 16Kuhmichel, Lew 12Kukla, Peter A. 6

L

Lallemant, Siegfried 37Lawton, Timothy F. 43Le Calvez, Joël H. 13Letouzey, Jean 33Lim, Siang J. 17Liro, Louis M. 10, 45Liu, Jianchang 17Lock-Williams, Susan 45

M

Machado, Marco Antônio P. 30Mann, Paul 36, 38Marton, Gyorgy 26Mascle, Alain 37Mathur, Vinod 10Matthews, Wendy 39McClay, Ken 48Meisling, Kristian 40Meltz, Robert 35Metzgar, Craig R. 17Meyer, David 35Milkov, Alexei V. 12Mohr, Markus 6Mohriak, Webster U. 25Molnar, Jim 27Murillas, Joseba 10

OOrange, Daniel L. 47

PPalmes, Stephen L. 34Pereira, Sergio R. 30Prinzhofer, Alain 37

RRoberts, Michael J. 17Rowan, Mark G. 5, 14, 18, 28, 43

SSchmitz, Julien 37Schoenborn, Greg 26Shaker, Selim S. 20Sherkati, Shahram 33Shimeld, John 23Smit, Dirk 48Sullivan, Sean 36, 38Szatmari, Peter 30

TTari, Gabor 27Thomson, Jim 47Trudgill, Bruce 29, 39Turner, Joshua C. 12

UUnderhill, John 15, 39Unternehr, Patrick 24Urai, Janos L. 6

VValasek, Dave 27Vendeville, Bruno C. 13Viana, Adriano R. 30Villalobos, Lorenzo 10Vines, John 40

A-324th Annual Gulf Coast Section SEPM Foundation Bob F. Perkins Research Conference—2004

WWalker, James D. 31Walters, Gary 27Weber, Nathan 45Williams, Mark 47

Wood, Lesli J. 36, 38

Y

Yough, Charles 45

A-4 Author Index

Salt-Sediment Interactions and - GCSSEPM Home · 24th Annual Gulf Coast Section SEPM Foundation Bob...

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