Northwest Africa Atlantic...

Ben Sayers

Northwest Africa Atlantic Margin – MSGBC Basin Prospectivity

Project Developer – Africa, Mediterranean & Middle East 27th May 2015

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3

Contents

Introduction

Geological Evolution of the MSGBC Basin

Exploration History

NWAAM Survey

Location and Acquisition

Play concepts and thermal modelling

Data Examples

Guinea Conakry

Guinea Bissau

AGC

Senegal/The Gambia

Mauritania

Summary

Conclusions

3


4


4

Geological Evolution of the MSGBC Basin

4 4

5

Mauritania, Senegal,

Gambia, Bissau, Conakry

(MSGBC)

Basin



Basin Evolution

The pre-rift section is made up of:

• Palaeozoic extensional tectonics in the south with horsts, grabens and tilted fault

blocks preserved from Pre-Hercynian; and

• Compressional tectonics in the north and central parts of the basin with effects

of Hercynian and Caledonian orogenies.



Basin Evolution

• The basin was formed at the end of the Permian in a Triassic Rift system.

• Lacustrine source rocks were deposited followed by continental Triassic clastics

1500m thick.

R

Triassic

R

Triassic



Basin Evolution

• A thick sequence of Triassic/Early Jurassic evaporites were deposited in the basin.

Up to 2000m of salt.

• Transgressing seas brought post-rift marine sediments.

R

Triassic

Early Jurassic

Early Jurassic



Basin Evolution

• 2000-3000m thick carbonates reservoirs were deposited form an active carbonate

factory.

• The platform both prograded and regressed through time.

R

Triassic

Early Jurassic

R

Mid-Jurassic

R

Mid-Jurassic



Basin Evolution

• Thick marine shales interbedded with marginal marine sandstones

deposited after the opening of the Atlantic in the Cenomanian.

• Black, bituminous Turonian shales were deposited marking the

maximum Cretaceous transgression

Mid-Cretaceous

R

Triassic

Early Jurassic

R

Mid-Jurassic

Mid-Cretaceous



Basin Evolution

• Senonian marine regression which culminated in deposition of

thick Maastrichtian sandstones. Up to 1200m thick.

• Tertiary sediments are unconformable and consist of marine

shales, carbonates with influx of sandy turbidites

R

Upper Cretaceous/Tertiary

R

R

Triassic

Early Jurassic

Mid-Jurassic

Mid-Cretaceous

R




Basin Evolution R

R

Mid-Cretaceous

Triassic

Early Jurassic

Mid-Jurassic

R


The Basin has undergone a complex history that can be divided

into 3 main stages of development:

• the pre-rift (Precambrian to Paleozoic)

• syn-rift (Permian to Early Jurassic)

• post-rift (Middle Jurassic onwards)


13


13

Exploration History

13 13



Adapted from Grant et al. 2013. Copyright SIEP BV.

FAN-1

SNE-1

(Source FAR website)

To date 177 exploration wells have been drilled in the basin with 115

encountering hydrocarbons – 66%!

Of the 110 offshore wells:

only 60 are in water depth of greater than 100m;

only 30 in water depths greater than 1000m;

And only 2 in water depths greater than 2000m.

Drilling Summary

14 14

100

MMBOE

950

MMBOE Avg. sized

Discovery


15


15

NWAAM Survey

15 15

Acquired in collaboration with:



NWAAM Survey



NWAAM

Ph1

NWAAM

Ph2

NWAAM Phase 1

Acquisition April – October 2011

Covered Area 220,000 km2

NWAAM Phase 2

Acquisition May - November 2012

Covered Area 140,000 km2

NWAAM Survey



NWAAM

Ph1

NWAAM

Ph2

NWAAM Survey

Streamer Length:

8km

Recording Chs:

640

Record Length:

14 sec (NWAAM Ph2)

9 sec (NWAAM Ph1)

More info: http://www.tgs.com/

http://www.tgs.com/specsheets/NW_Africa_Passive_Margin_Spec Sheet.pdf





M. Brownfield and R. Charpentier, 2003

PR

E-R

IFT

NWAAM Regional Stratigraphy

SY

N-

RIF

T

PO

ST-R

IFT

E

AR

LY

PO

ST

-

RIF

T

R

R

Source rocks

Clastic reservoir

Limestone reservoir

Silurian MARINE SOURCE ROCK ?

Devonian RESERVOIR

Triassic LACUSTRINE SOURCE ROCK ? Triassic RESERVOIR

Cenomanian / Turonian MARINE SOURCE

ROCK

Cretaceous – Tertiary RESERVOIR

Jurassic

Cenomanian

Cre

tace

ous

Maastrichtian

Triassic

Aptian MARINE SOURCE ROCK

Albian RESERVOIR

R

R

R

R

R

R

R



Play Concepts

Silurian Sourced Possible: Silurian present across majority of North

Africa and Paleozoic sandstones (15-20% Ф)

present in Bove Basin along with 400m thick

Silurian “Buba Shale” source rock

Triassic Hypothetical: Lacustrine sources charging

Triassic clastics sub-salt. Works in

Morocco and Newark basin

Aptian-Albian PROVEN: FAN-1 and SNE-1

Turonian/Cenomanian Sourced PROVEN: Lots of wells including – Jammah-1 GB-1, Sabu-1, Sheepshead-1

Jurassic Carbonate Reservoir PROVEN: Offshore Cape Timiris-1, Loup de mer-1

Buried Hills

Buried Hills PROBABLE: Albian shelf eroded by Senonian unc., karstified, then sealed

by upper Cretaceous to lower Tertiary shales & marls. Evident on Seismic Miocene Sources Hypothetical: Shales deposited and Miocene

reservoirs are proven so would just require

sufficient burial

Salt related Salt traps and structures are proven

throughout the basin. Chinguetti Field etc…


21


21

NWAAM Data Play Examples

21 21



Coppolani-1 well was un-economical discovery. Oil found in the Maastrichtian, charged

Type II Turonian oil.

NWAAM - Mauritania Sub Basin

Top Syn-Rift

Sea Bed

Top Lower Miocene

Senonian Unc.

Top Turonian

Top Neocomian

Top Sag

Top Aptian

Eocene-Oligocene

Carbonates

Syn-kinematic

sand deposition?

Lower Aptian-

Neocomian updip

brightening

Salt-related sand

deposition?

Analogous to

Labeidna field?

Analogous to

Chinguetti field?

Senonian Unc.

Sea Bed

Top Lower Miocene

Top Turonian

Coppolani-1



NWAAM – Southern Mauritania Sub Basin

E W Faucon-1 WD = 1164m TD= 4170m

• Salt diapir creates traps for updip migration

• Faucon-1 drilled HC bearing sandstones from the Lower Campanian

• Salt present throughout the majority of the basin.

Sea Bed

Senonian Unc.

Top Turonian

Top Aptian

Top Neocomian

Top Jurassic

Top Lower Miocene



• 2 recent discoveries in the basin, both Albian sandstone reservoirs sourced from

Aptian sources.

• FAN-1 is a set of stack fans

• SNE-1 - 96 metre oil column in 24% PHIE shelf edge sands

• FAN-1 & SNE-1 have a combined p-50 reserve estimate of over a Billion barrels

of Oil of API 32°

NWAAM – Sangomar Basin

TW

T (s

ec)

E W

FAN-1 WD = 1427m TD= 4927m

SNE-1 WD = 1100m TD= 3000m

Top Syn-Rift

Sea Bed

Top Albian

Top Oligocene

Top Jurassic

Top Senonian

Image credit: Cairn Capital Markets Day, 11th May 2015



• Similar structuration to Sangomar basin despite being 150km further south

• SNE-1 analog further up-dip which has an AVO response showing stacked sands.

• Salt dome post-salt clastic play?

• Evidence of Pre-salt Triassic play

NWAAM – Casamance Basin

E W

Triassic source

rocks?

FAN-1 analogue

SNE-1 analogue

8km

Top Syn-Rift

Sea Bed

Top Albian

Top Oligocene

Top Jurassic

Top Senonian

Top Aptian



• Contractional structures and fault bounded brightening

• Salt tectonics have controlled sand deposition

• Amplitude anomalies in the Lower Albian related to HC charge or high porosity sands

Cenomanian

source interval

HC related

brightening?

Fault bounded updip

brightening

TW

T (

se

c)

NWAAM - Casamance Sub Basin (AGC)

Top Syn-Rift

Sea Bed

Top Albian

Top Jurassic

Top Aptian



• Hydrocarbon Related Diagenetic Zones (HRDZ) indicate a highly charged

hydrocarbon system.

• Aptian-Albian sediments pinching out against the Jurassic carbonate platform

and showing high amplitude anomaly.

• Aptian sand channels pinching out over the flank of salt.

Albian-Aptian sands

Updip brightening or charged sands Salt dome

Aptian channel sands with

updip pinchout over flank

of salt diapir

HRDZ?

NWAAM - Southern Sub Basin (Guinea Bissau)

Top Syn-Rift

Sea Bed

Top Albian

Top Oligocene

Top Jurassic

Top Senonian

Top Aptian

Sea Bed

Top Albian

Top Oligocene

Top Senonian

Top Aptian



N S T

WT

(se

c)

• Diapir piercing Late Cretaceous sediments.

• shallow water sub-crop unconformity traps at the edge of the hinge zone.

• syn-rift sands below the salt.

Syn-Rift sands?

Sub-crop

unconformity traps

Salt related

structures

NWAAM - Southern Sub Basin (Guinea Bissau)

Top Aptian

Top Albian

Top Jurassic

Top Syn-Rift

Top Oligocene

Top Senonian



• Thinner Mesozoic sediments due to basement geometry.

• Triassic source rocks in oil window

• Possible evidence of presence of Silurian sources and Devonian clastics

TW

T (s

ec)

Pre-rift

Sediments

NWAAM - Offshore Guinea Conakry

N S

Early syn-rift

Sediments

Top Aptian

Top Jurassic

Top Syn-Rift

Top Oligocene

Top Senonian

Sea Bed



Northern Sierra Leone

A series of Mid-Albian (syn-rift) fault terraces with some bright amplitudes

within the fault blocks that relate to sand-prone sequences within the syn-rift

sediments.

Top Aptian

Top Cretaceous

Base Neogene

Sea Bed

Top Miocene

Top Eocene



E W

NWAAM – Southern Mauritanian Sub Basin

Tortue-1 WD = 2668m TD= 4630m

• 150m gross hydrocarbon bearing interval in the Upper Cenomanian

• 160m gross interval with 3 distinct MULTI-Darcy reservoirs in Lower Cenomanian

• Other plays deeper in the Cretaceous are also expected



Line Bend

CM-7

E S W

Faulted

Blocks

Updip

closures

Albian slope fan

sand channels

NWAAM - Casamance Sub Basin (AGC)

Top Syn-rift

Sea Bed

Senonian Unc.

Top Albian

Top Aptian

Top Jurassic



Syn-Rift

Sandstones?

NWAAM - Northern Sub Basin (Offshore The Gambia)

1.8 seconds (TWT)

3.7 seconds (TWT)

FAN-1 Analogue

SNE-1 Analogue

Top Syn-rift

Sea Bed

Senonian Unc.

Top Albian

Top Jurassic

Top Aptian



Image credit: Africa Petroleum Natural Resources Forum, April 2015

Lamia

Acacia

Rosewood

Sami Paprika

Nema

Mahogany

Alhamdulilah

Albian Shelf Edge

Albian-Santonian Deepwater play

10 km

NWAAM – The Gambia 3D

TGS also have a multi-client 3D survey offshore The Gambia,

2,500 sq. km acquired in 2011

SNE-1 Analogue FAN-1 Analogue



There are three main petroleum systems present in the MSGBC basin:

• A post-rift sequence:

• Source - proven Aptian / Albian / Turonian;

• Reservoirs - Upper Cretaceous / Tertiary clastic rocks and Jurassic

carbonates;

• Seals - Upper Cretaceous/Tertiary marine shales or allochthonous salt.

• A pre-salt sequence:

• Source rocks - Triassic lacustrine;

• Reservoirs - Triassic syn-rift clastic rocks and/or Jurassic early post-

rift limestones;

• Seals - interbedded shales or salt.

• A pre-rift Silurian/Devonian level:

• proven onshore and probably extending offshore in the shallow shelf

area of Guinea Conakry.

Summary - Prospectivity



Basin and Sub-basin evolution and architecture is controlled by pre-

existent basement geometry, syn-rift faults, transform movements and salt

tectonics.

The numerous discoveries in the Basin prove the existence of working

petroleum systems along the North West African Passive Margin and

FAN-1 and SNE-1 prove these systems can be commercial.

Potential DHIs such as bright spot and gas related features have been

highlighted.

Conclusions

The complex structural evolution has led to the formation of numerous

structural and stratigraphic traps identified across the study area.



Acknowledgments

TGS for Interpretation and modelling work:

Dario Chisari, Peter Conn, Ian Deighton, Roel Dirkx, Jennifer Halliday, Cian O’Reilly,

and Erika Tiboucha.

External references: African Petroleum (interpretation of TGS 3D) =

http://www.africanpetroleum.com.au/sites/default/files/u147/AP_NaturalResourcesForum_24Apr2015.p

df Last accessed 26th May 2015

Cairn Energy (FAN-1 and SNE-1 geoseismic and pressure curve data) = http://files.the-

group.net/library/cairnenergy/news_presentation/CapitalMarketsDay11MayPresentation.pdf Last

accesed 26th May 2015

FAR Limited (3D Interpretation of SNE-1 and FAN-1) = http://www.far.com.au/wp-

content/uploads/2015/04/20150413-Investor-presentation.pdf

Grant, C. et al. 2013. Hunting for deepwater subtle traps, from Geology to Technology. The 5th Biennial

Petroleum Geology Conference. Bergen, Norway. March 2013.

http://www.africanpetroleum.com.au/sites/default/files/u147/AP_NaturalResourcesForum_24Apr2015.pdf



http://files.the-group.net/library/cairnenergy/news_presentation/CapitalMarketsDay11MayPresentation.pdf




http://www.far.com.au/wp-content/uploads/2015/04/20150413-Investor-presentation.pdf








Thank you


Thank you


Ben Sayers

+44 208 339 4239

[email protected]

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