A Review of the Geology

and Petroleum Systems

in the Eastern Gulf of Guinea,

West Africa

Richard Bray

Exploration Consultants Limited

Exploration Consultants Limited, Highlands Farm, Greys Road,Henley-on-Thames, Oxfordshire, England

Location Map

Slide 1

Dakar

Banju l

Bissau

Conakry

Freetown

Monrovia

Abi djan Accra

Portnovo

PortHarcourt

Y aounde

Kribi

Malabo

Librevi lle

Port Gentil

Sette Cama

Brazzaville

Luanda

Windhoek

Lüderitz

GHANA

M AUR IT

SENEGAL

CÔTED’IVOIRE

BENIN NIGERIA

CAMEROON

EQUATORIALGUINEA

GABON CONGO

D. R. CONG O

ANGOLA

NAMIBIA

Espoir30 mmbbls

Zafiro>500 mmbbls

N’Kossa>200 mmbbls

Benguela Complex>2 billion bbls

Erha1 billion bbls

Bonga750 million bbls

Agbami1 billion bbls

Ceiba>200 mmbbls

Girassol/DaliaComplex> 2 billion bbls

Kizombo Complex>1.5 billion bbls

Kuito>2 billion bbls

Deep Water Discovery

Deep Water Production

Boabab

Akpo1 billion bbls

Slide 2

Discovery History

YEAR

0

1000

MMbo

recoverable

2000

3000

4000

1990 1980 1970 1960 1950 1940

Deep waterplays

Conventionalplays

Slide 3

EasternGulf of GuineaHydrocarbonOccurrences

Ilha de Príncipe

llha de São Tomé

GABON

CAMERO ONNI GERIA

SAOTOME

oil seeps

oil seeps

SanagaSud

Ceiba

AlbaZafiro

Kribi

Okume

kilometres0 200

5°E

0°

10°E

5°N

Isla deAnnobón

llha de São Tomé

SAO TOME

kilometres0 200

5°E

0°

5°S

Salado

Orange

Puntadel Este

Lüderitz

Pelotas

Walvis

Santos

Namibe

Campos

Kwanza

EspiritoSanto Lower

Congo

Almada

BahiaNorte

Reconcavo

PortugarDouala

Sergipe-Alagoas

Gabon

WestAfrica

South America

Walvis Ridge

Recife

Rio MuniPlate edge

Present-daycoastline

Basins

30°S

60°W

Slide 4

Early Cretaceous Reconstruction

AFRICASOUTH

AMERICA

Slide 5

South Atlantic Mesozoic Basins

BenueTrough

IvoryCoastBasin

NigerDelta

GabonBasin

DoualaBasin

CongoBasin

AngolaBasin

PelotasBasin

SantosBasin

Campos Basin

Jequitinhonha,Espiroto Santo

Basins

Bahia Sul Basin

Sergipe-AlagoasBasin

MaranhaoBasin

R-T-JGrabens

ParanaBasin

Portugar Basin

0°30°W

40°S

20°S

0°

20°N

J.B. Meyers et al, 1996

Slide 6

Regional Tectono-stratigraphy

?

CHRONOSTRATIGRAPHY

SAN.CON.

PLI-HOL

PRECAMBRIAN

TECTONOSTRATIGRAPHY

GABONBASIN

RIO MUNIBASIN

DOUALABASIN

? ? ?

BENUETROUGH /

NIGER BASINTECTONIC EVENTS

DRIFT II

TRANSITIONAL

RIFT III

RIFT II

RIFT I

DRIFT III

MIDTERTIARYUPLIFT

LATETERTIARYUPLIFT

sliding

NIGER DELTA

BUILD-OUT

Santonian tectonicevent - uplift,sliding

early sliding

SALT

MOVEMENT

RIFTING

DRIFT I

Slide 7

Cross-section of Margin Evolution - 1

LATE APTIAN

EARLY SEPARATION

LATE SEPARATION

ALBIAN-CENOMANIAN

Oceaniccrust

Sheared-margincrust

Break-upunconformity

Salt basin

Magmaticunderplating?

LATE ALBIAN UPLIFT

Upper-levelsliding

ContinentalCrust

Slide 8

Cross-section of Margin Evolution - 2

LATE SEPARATION

SANTONIAN

UNCONSTRAINEDOPENING

MIOCENE -QUATERNARY

Senonianunconformity

Growthsequence

Onlappingsequence

Lower-levelsliding

MioceneunconformityLate sliding

MID & LATE TERTIARY, & QUATERNARY UPLIFT

LATE CRETACEOUS UPLIFT

Slide 9

EasternGulf of GuineaGeologicalSetting

Isla deAnnobón

Ilha dePríncipe

llha deSão Tomé

GABON

CAMEROONNI GE RI A

SAOTOME

5°E

0°

10°E

5°N

0 200kilometres

Slide 10

Petroleum

Systems

Gabon Basin Rio Muni Basin

SAN.CON.

PLI-HOL

PRECAMBRIAN

SAN .CON.

PLI -HOL

PRECAMBRIAN

Slide 11

Petroleum

Systems

Douala/Kribi-Campo Basin

Niger Delta

?

SAN.CON.

PLI-HOL

PRECAMBRIAN

? ? ?

SAN.CON.

PLI -HOL

PRECAMBRIAN

Slide 12

EasternGulf of GuineaPetroleumSystems

CAMERO ONNI GERIA

GAB ON

SAOTOME

NGOLO

IKIJA-1

DORO

NNWAUKOT

ZAFIRO

ISONGOALBA

CEIBA

AGBAMI

AKPO-1

Port Harcourt

Bata

Libreville

Malabo

Ilha de Príncipe

llha de São Tomé

oil seeps

oil seeps

Ceiba

AlbaZafiro

Okume

Agbami

Akpo SanagaSud

Kribikilometres0 200

5°E

0°

10°E

5°N

Late TertiarySource Kitchen

Area Sourced fromLate Tertiary Kitchen

Mid CretaceousSource Kitchen

Area Sourced fromMid Cretaceous Kitchen

Early CretaceousSource Kitchen

3

2

1

Slide 13

Rio Muni-Cameroon Cross-section

West East

Early Cretaceoussource rocks.

Mid-Cretaceoussource rocks

NEOGENE

Ceiba

TOE THRUSTFAIRWAY

Miocenesource rocks

TERRACE UPLIFT

COMPLEX

DEEP WATER FAN/CHANNEL DEVELOPMENTSGRAVITY SLIDING ALONG SLOPE

BASIN SLOPE PLATFORM

Kribi-Sanaga SudFields

Slide S1

Northern Rio Muni, Seismic Section

Slide S2

Rio Muni, Seismic Section

Slide 14

Northern Equatorial Guinea - Northern CameroonCross-section

Shale diapir-associatedstructures

Benin

Moudi

Tsavorita

UPPER QUA IBOE

LOWERQUA IBOE

Zafiro

Amatista

AKATA

ISONGO

Alba

BONITO

AKATA

LATE CRETACEOUS

OCEANIC CRUST

SOUELLABA

LOGBABA

OCEANIC CRUST

Toe-thruststructures

Oil migrating fromCretaceoussource rocks

Deep water sands

Oil seeps associated withCretaceous exotics

Cameroon Volcanic Line

Isongo

Post-rift Marine(Albian-Turonian)

N i g e r D e l t a - R i o d e l R e y B a s i n Douala Basin

North-west South-east

MATANDA

LOGBADJECK

WOURI

Channel/fan sands

CONTINENTAL CRUST

S anaga Delta

MUNDECK

Apt-AlbianSource RocksPost-rift SRs

Albian-Cen

N I G E R I A E Q U AT O R I A L G U I N E A C A M E R O O N

M’Via

Matanda

Souellaba

Slide S5

Offshore Bioko, Seismic Section

North-west South-east

Slide S6

Regional Seismic Section

ALBAFM.

QUAIBOE FM.

PLIOCENE

ISONGO FM.

(MIOCENE)

Base Tertiary?

WOURI

FM.

SOUELLABA

FM.

LOGBABA-

LOGBADJECK

FM.

MUNDECK

FM.

Base Pliocene

Base Miocene

Senonian Unc.

Slide 15

• Abundant, rich, oil-prone source rocks

• Thick, clean turbidite sands

• Structural & stratigraphic traps

• Late/ongoing hydrocarbon generation

KEYS TO THE WEST AFRICA

DEEP WATER PLAY

Slide 16

Eastern Gulf of GuineaOpen Deep WaterAcreage, 2001

7°E 8°E 9°E 10°E

4°N

3°N

2°N

1°N

NIGERIACAMEROON

Ilha de Principe

Riomuni

GABON

Corisco

SAOTOME

Equatorial GuineaOpen Deep WaterAcreage

Newly allocatedblocks in 1999Deep WaterLicence Round

Deep Water Cameroonblocks awarded 2001

Currently licensed blocks

Currently open acreage

0 200kilometres

Isla deAnnobón

llha de São Tomé

0 200kilometres