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Basin Analysis and Petroleum Exploration ENCH Dr. Barry McNamara Sept 14 to Dec 7 2005

Transcript of Ench week01

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Basin Analysis and Petroleum

Exploration

ENCH

Dr. Barry McNamara

Sept 14 to Dec 7 2005

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Topics for Week 1

Course overviewo scope, expectations, format, grades, projects, exams

Instructor and students: background

Basin analysiso sedimentary basins

o what is basin analysis

Tools of the geoscientisto plate tectonics, sequence stratigraphy, seismic stratigraphy

Petroleum systemo petroleum charge, migration, entrapment

Exploration engineers and basin analysis

Reading material

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Course Schedule and ContentClass Topic

Sept 14

Week 1

Introduction to Course and Material

Review and discussion of concepts

Sept 21

Week 2

Example of basin analysis: Gulf of Suez Rift Basin

Basins I: description of basins, plate tectonics, basin classification and

tectonic setting

Sept 28

Week 3

Basins II: basin classification (continued), basin models of subsidence

and sedimentation

Oct 5

Week 4

Basin Fill I: Stratigraphy and sedimentology; tools used, dating and

correlation

Oct 12

Week 5

Basin Fill II: Facies models, basin mapping; sequence s tratigraphy

Oct 19

Week 6

Basin Fill III: Sequence stratigraphy (continued), seismic stratigraphy

Oct 26

Week 7

Due Today: Selection of basin/petroleum system for main class

project

Basins III: Regional and global stratigraphic cycles

Nov 2

Week 8

Mid Term Exam (tentative)

Review selected basin example

Nov 9

Week 9

Petroleum System I: The petroleum system

Nov 16

Week 10

Student seminars

Petroleum System II: Field size distribution, play concepts

Nov 23

Week 11

Student seminars

Selected geologic topic: Carbonate models: basin fill and sequence

stratigraphy

Nov 30

Week 12

Student seminars

Carbonate models (continued): sequence stratigraphy, reservoir

development

Dec 7

Week 13

Student seminars

Basin modeling software demonstration

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Format of Course

Lecture to cover most material you will see in Basin

Analysis: will review material from textbook (Miall,

2000) as well as selected reading material from

reference texts and assigned reading.

Cover some basin examples to illustrate concepts you

will see and report on in your research project.

Students may be asked to discuss some of their work

on their research paper as it pertains to lecture

material.

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Course Description

The course is designed to provide a framework for

understanding the geologic description of sedimentary basins,

within the context of petroleum systems, with application to

exploration for petroleum reservoirs. Course lectures and

reading material will cover: classification of sedimentary basins

and their plate tectonic settings; mechanism of subsidence and

thermal history of sedimentary basins; geological and

geophysical methods of basin mapping; depositional systems,

basin fill and facies models; thermal maturity of source rocks;

generation and migration of hydrocarbons; controls on reservoir

quality in clastic and carbonate rocks; petroleum resource

assessment and play concepts on basin scale.

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Course Objectives

to present the concepts of Basin Analysis to

exploration engineers

to place Basin Analysis within the framework of tools

and concepts for petroleum exploration that are in use

by exploration geoscientists

to prepare exploration engineers to communicate with

geoscientists to improve the decision making process

in evaluating basins for petroleum exploration

Independent study of selected basins to become more

familiar with basin analysis

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Level of Detail

Topics covered at a level sufficient to:

introduce or review geoscience subjects at a level

appropriate for exploration engineers

increase awareness of types of geoscience

information available to describe the exploration

potential of petroleum systems within a sedimentary

basin

emphasize the role of the exploration engineer in

contributing to the exploration process of Basin

Analysis

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Grading of Work

Examinations:

There will be one mid-term examination. The examination will be closed book. Late October/early November.

Final Grades:

The final grade will be determined on the basis of:

Mid term exam 30%

Basin analysis project 50%

presentation: 10%

written report 40%

Classroom work 20%

Project due on Dec 14; no late projects accepted

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Independent Work

A written research report (including references), and presentation of report to class by each student, will be required on a specific basin. Basin will be selected by student with approval of instructor. Reports and presentations will be marked for final grades. Format of report will follow a “basin analysis”.

Students will be expected to participate in class discussions, to discuss the basin project they are working on as it relates to topics being covered in class, and to present interim reports on their basin analysis project as required.

Readings (books, journal articles) will be assigned each week as required.

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Other MaterialsReference Material

Allen, P.A., and Allen, J.R., 1990. Basin Analysis: Principles and Applications,

Blackwell Scientific Publications, Oxford, 451p

C. J. Busby and R. V. Ingersoll, editors, 1995. Tectonics of Sedimentary Basins,

Blackwell Science, Cambridge, MA, 579 p.

Einsele, G., 2000. Sedimentary Basins: Evolution, Facies, and Sediment Budget,

792 p.

Tissot, B.P. and Welte, D.H., 1984. Petroleum Formation and Occurrence

Useful Websites

USGS: This Dynamic Earth: the Story of Plate Tectonics

http://pubs.usgs.gov/publications/text/dynamic.html

USC Sequence Stratigraphy Web

http://strata.geol.sc.edu/index.html

USGS: The Earth’s Crust

http://quake.wr.usgs.gov/research/structure/CrustalStructure

USGS World Petroleum Assessment 2000.

http://pubs.usgs.gov/dds/dds-060/index.html

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Instructor

Dr. Barry McNamara

Education:o BSc (‘84) St Francis Xavier University, Antigonish, Nova Scotia

o MSc (‘89), PhD (‘95), Reservoir Geology, University of Calgary

Senior exploration geologist, Innova Explorationo Actively working to find oil and gas

Work experience: Chevron, Gulf Canada, Santos,

Baytex, Vintage Petroleum, Innova Exploration;

Canada and Australia

Work experience as geologist and reservoir engineer

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What is Basin Analysis

Basin analysis involves making an interpretation of the formation, evolution, architecture and fill of a sedimentary basin by examining geological variables associated with the basin.

Basin analysis provides a foundation for extrapolating known information into unknown regions in order to predict the nature of the basin where evidence is not available.

A basin model is built on a framework of geological surfaces that are correlated within the basin. This stratigraphic framework can be expressed in terms of rock type (lithostratigraphy), fossil content (biostratigraphy), age (chronostratigraphy), or rock properties such as seismic velocity (seismic stratigraphy).

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Sedimentary Basins

Sedimentary Basin: A depression in the crust of the

Earth in which sediments accumulate. Formed by

plate tectonic activity. Continued deposition can cause

further depression or subsidence.

If rich hydrocarbon source rocks occur in combination

with appropriate depth and duration of burial,

hydrocarbon generation can occur within the basin.

approx 575 sedimentary basins identified worldwide

approx 215 known productive

approx 360 non-productive

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onshore (green) and offshore (purple)

Worldwide distribution of sedimentary basins

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USGS World Petroleum Assessment 2000

Assessed 76 geologic provinces containing

95% of non-US known petroleum reserves

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Importance of Basin Analysis

Oil and gas exploration is all about finding economically

productive hydrocarbons. Better understanding of

sedimentary basins through Basin Analysis will improve

decision making for exploration projects

New (immature, undrilled) basins can have a systematic

treatment for assessment of exploration potential

Re-look at mature basins to provide new exploration targets

Required integration of geoscientists and engineers can

produce new ideas, better decisions

“The classification of basins does little to improve our

hydrocarbon volume forecasting ability.” (Bally and

Snelson, 1980)

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Classification of

tectonic setting

of giant oil fields

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Remaining Reserves of Crude Oil by Basin

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World Endowment of Crude Oil, Natural Gas and NGL Liquids

(Source: USGS World Petroleum Assessment 2000)

Note significant reserves to be added through reserve growth in

established play areas and petroleum systems.

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Geoscience Effort in Basin Analysis

Basin analysis for exploration can be described as the integration of the following 3 components

Controls on development of the sedimentary basinplate tectonic and paleogeographic history

Stratigraphy and sedimentology of the basinbasin fill

The petroleum systemsource, maturity, migration, trap, seal

Significant geoscience effort is required to prepare each of these components of the basin analysis; multidisciplinary approach

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Controls on Development of the Sedimentary Basin

plate tectonic settings of basin formation

basin morphology over time

latitude of the basin

geothermal gradients and heat flow profiles

tools in use:o geophysical tools: seismic, gravity and magnetics

o interpretation of seismic data

o palinspastic restoration of balanced restored cross sections

o surface geology

o depositional and erosional analysis

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Plate Tectonics: Review of Earth Structure

(from USGS website)

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Convection Engine Driving Plate Tectonics

(http://www.glossary.oilfield.slb.com/DisplayImage.cfm?ID=154)

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Thickness of Crust

(http://quake.wr.usgs.gov/research/structure/CrustalStructure/)

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Lithospheric Plates

(http://pubs.usgs.gov/publications/text/slabs.html)

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Convergent Boundary

(http://pubs.usgs.gov/publications/text/understanding.html#anchor6715825)

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Specifics of Basin Fill

sequence stratigraphy

stratigraphic interpretation, geologic time

megasequences, major unconformities

facies models

basin wide chronostratigraphic framework

tie to seismic markers

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Seismic Facies and Reservoir Architecture

(Fugelli and Olsen, 2005)

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Global Sea Level Fluctuations

(Vail et al, 1977)

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Geologic Time Scale

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Numerical Modeling of Basin History

Decompaction and “Backstripping”

Account for subsidence, thermal history, uplift

Example: North Sea

o Backstrip from present to near syn-rift

o Acknowledge two rift events

o Allow for Palaeocene uplift by Iceland plume

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Java Stretch and Flex Decomp

Worked examples from the

Northern North Sea

multiple-rift basin

An Example of Basin

Modeling

http://www.badleys.co.uk

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Flex Decomp: Present-day cross-section

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Flex Decomp: Layers 1 and 2 removed

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Flex Decomp: Layers 3 and 4 removed460m Iceland Plume support applied at 55Ma

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Flex Decomp: Layers 5 and 6 removed

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Flex Decomp: Layer 7 removedBase Cretaceous at 140Ma close to syn-rift

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Petroleum System

appraisal of petroleum generating kitchen

source rocks, kerogen types

source rock maturity over time

fluid flow and pressure systems

migration path from source to trap

volume of generated hydrocarbons

reservoir quality and fairway assessment

porosity destruction and formation in subsurface

seal effectiveness

prediction of hydrocarbon composition

geochemical modeling/thermal maturity

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Petroleum System

Geologic components and processes necessary to generate and store

hydrocarbons, including a mature source rock, migration pathway,

reservoir rock, trap and seal. Appropriate relative timing of

formation of these elements and the processes of generation,

migration and accumulation are necessary for hydrocarbons to

accumulate and be preserved. The components and critical timing

relationships of a petroleum system can be displayed in a chart that

shows geologic time along the horizontal axis and the petroleum

system elements along the vertical axis. Exploration plays and

prospects are typically developed in basins or regions in which a

complete petroleum system has some likelihood of existing.

http://www.glossary.oilfield.slb.com/default.cfm

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The Petroleum System

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Petroleum Generation: Kitchen

maturation of organic matter hydrocarbon generation

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Kerogen

The naturally occurring, solid, insoluble organic matter that

occurs in source rocks and can yield oil upon heating. Typical

organic constituents of kerogen are algae and woody plant

material. Kerogens have a high molecular weight relative to

bitumen, or soluble organic matter. Bitumen forms from

kerogen during petroleum generation. Kerogens are described

as Type I, consisting of mainly algal and amorphous (but

presumably algal) kerogen and highly likely to generate oil;

Type II, mixed terrestrial and marine source material that can

generate waxy oil; and Type III, woody terrestrial source

material that typically generates gas.

Modeling thermal maturity of kerogen is important to

understand oil and gas generation

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Need for Engineering Component

There are significant hydrocarbons to be discovered

and produced in known basins and petroleum

systems; using existing infrastructure and re-

examining mature basins will continue to be

important

Provide reality check; subsurface pressure regime,

flow rates, risked reserve estimates

Apply additional tools: economics, fracture

stimulation, alternative development and sales

scenarios

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Basin Analysis and Petroleum Exploration

“... it is not implied that engineering concepts can replace geological methods in the search for oil and gas, or that the exploration geologist should become an expert in reservoir engineering. It is believed, however, that some reservoir engineering concepts may be used to implement geological methods and that a close cooperation between engineering and geological talent may contribute substantially to an exploration program.” (Arps, 1963)