A RE-THINK ON THE

A RE-THINK ON THE STRATIGRAPHY OF THE NIGERIAN CHAD (BORNU) BASIN AND ITS IMPLICATIONS ON PETROLEUM POTENTIALS

Abubakar, Muhammad Bello

National Centre for Petroleum Research and Development, Abubakar TafawaBalewa University, Bauchi, Nigeria

Outline• Introduction• Stratigraphic Discrepancies• Foraminiferal Distribution & Palaeoenvironment of So‐called “BimaSandstone” Across Some Boreholes

• Age & Palaeoenvironmental Correlation Across Contiguous Basins• Correlation Across Contiguous Basins & New Stratigraphic Proposition of the Chad (Bornu) Basin

• Schematic Tectono‐Depositional Model of Gongola & Chad (Bornu) Basins & Its Implication to Petroleum Potentials

• Summary• Conclusion

Modified from Saugy (1987)

From Genik (1993)

CHAD BASIN

NEOG. – QUAT.VOLCANICS

BENUE TROUGHBASIN

BASEMENT

DEPTH TO BASEMENT

>5000m

3000-5000m

1000mCONTOUR

WELLS1 Gubio SW-12 Wadi-13 Kinasar-14 Kanadi-15 Albarka-16 Mbeji-17 Kemar-1

23

4

5 6

NIGER

CHAD

CAMEROON

1

100km

7

Introduction

From Genik, 1993

West and Central African Rift System showing the locations of oil and gas discoveries(from United Reef Limited Report, 2004).

Introduction…contd

Stratigraphic Discrepancies

• Outcrop & seismic studies identified the presence of Gombe & Kerri Kerri Fms in the basin

• Fika Shales were mostly considered Con. – Sant. ‐Maastr. with unconformable top

• Bima Sandstone was considered Cenomanianat the top & of sst/sh/lstfacies (including the so‐called “Pre‐Bima”)

• Bima Shale Member was apparently first introduced by Simon‐Robertson reports.

Quart.(Pleist.)

Mioc.‐Plioc.

Eocene‐Olig.

Palaeocene

Maastr.

Camp.

Sant.

Coniac.

Turon.

Cenom.

Albian

Aptian

Pre‐Aptian

Pre‐Cambrian

AGE

Upper

Upper

Upper

Upper

Lower

Lower

Lower

Lower

Lower

Lower

Lower

Upper

Upper

Upper

Middle

Middle

Middle

Carter et al.(1963)

Petters(1982)

Avbovbo et al.(1986)

Petters(1991)

Simon‐Robert.(1991)

Okosun(1995)

Olugbemiro(1997)

Alalade & Tyson(2010)

Chad Fm.

Kerri Kerri Fm.

Gombe Fm.

Fika Shales

Gongila Fm.

Bima Sandst.

? ?

? ?

Chad Fm.

Kerri KerriFm.

Gombe Fm.

Fika Shales

Gongila Fm.Bima Sandst.

Pre‐Bima?

Chad Fm.

Kerri KerriFm.

Gombe Fm.

Fika Shales

Gongila Fm.

Bima Sandst.UnnamedUnnamed

Chad Fm.

Kerri KerriFm.

Gombe Fm.

Fika Shales

Gongila Fm.

Bima Sandst.

? ?

? ?

?

Chad Fm.

Gombe Fm.

Kerri Kerri Fm.

Fika ShalesGongila Fm.

Bima Shale M.Bima Sand M.Pre‐Bima

Chad Fm.

Kerri KerriFm.

Fika Shales

Gongila Fm.

Bima Sandst.Pre‐Bima? (Sst‐Sh)

Bima Fm. (Sst‐Sh‐Lst)

Gongila Fm.(Sh‐Lst‐Sst)

Fika Shales

Gombe Fm.

Kerri KerriFm.

Chad Fm.

? ?

? ?

Chad Fm.

Fika Shales

Gongila Fm.

Bima Sandst.

Basement

BasementBasement

Basement

Basement

Basement Basement

A

A’

B

B’

C

C’

A A’

B B’

C C’B1

B2&3Y

PfPkPdf

Kk g

Stratigraphic ….. Contd.

Geological Map around Dumbulwa‐Bage High (Map from Zaborski et al., 1997)

0m

500

1000

1500

2000

2500

3000

3500

4000

4500

? ?

CHAD FM

FIKA SHALE

GONGILA FM

BIMA FM

PRE‐BIMA?

TD 3650m

TD 4645m

TD 3048m

TD 3475m

TD 3650m?

Albian

(?) ‐

Ceno

man

ian

Turonian

Coniacian–

Santon

ian

Miocene

(?) –

Pleistocen

e

Gubio SW‐1 Kinasar‐1 Kanadi‐1 Albarka‐1 Mbeji‐1

Argillaceous fine‐ Very fine sandsts

Terrigenous mudsts

Marls

Shales

Black shales

Limest

Calc. sst

Coarse sst

VolcanicsBasement

Sandy mudst

Intrusives

Argillaceous siltst

Argillaceous sandst

Silty mudst

Shales

Turonian

(Cret. scab

ratus/mulleri

Zone

)

?Con

iacian

–Santon

ian(Droserid

itess

enon

icus

Zone

)Ca

mp. –

Maa

str.

(Proteac.

deha

nii

Zone

)

Fika

Shale

600m

700

1480

TD 1780m

Kemar – 1Stratigraphic ….. Contd.

• Fika Shale was considered Turonian –Maastrictianwith an unconformity towards its upper limit

Develope

d from

Sim

on‐Rob

ert. Re

port, 1

991 & Olugb

emiro

, 199

7

Reconstructed from Adegoke, 2012

From Olugbemiro, 1997From Simon‐Robertson Report, 1991

Gubio SW‐1

Foraminiferal Distribution & Palaeoenvironment of So‐called “Bima Sandstone Across Some Boreholes

From Simon‐Robertson Report, 1991

Gubio SW‐1

Foraminiferal Distribution & Palaeoenvironment of So‐called “Bima Sandstone Across Some Boreholes

Age & Palaeoenvironmental Correlation Across Contiguous Basins

Pre‐Bima

Lower Bim

a(B1)

Middle Bima(B2)

Upp

er Bim

a(B3)

YoldeFm

3000

2700

2400

2100

1800

1500

1200

900

600

300

0m

YoldeFm

Upp

er & Low

erBima(B2&

B3)

Lower Bim

a(B1)

& ?Pre‐Bima)

Pind

igaFm

GombeFm

Kerri KerriFm

20‐500

30‐1100

300‐900

300‐1500

300‐1700

200‐1000

300‐2500

Sokor‐2 (Argilede Sokor)

Sokor‐1(Alternance de

Sokor)

Madama/GresMassif

Yogou/Agadem

Donga/Zoo Baba

Sedigi/Alaniara

K1/Tefidet

HolocenePleistocene

Pliocene

Miocene

Oligocene

Eocene

Palaeocene

Maastrichtian

Campanian

Santonian

Coniacian

TuronianCenomanian

Lower Cretaceou

s (Barria

sian

–Albian

)

Jurassic& Older

Pre‐Cambrian

Thickness(m)

Pre‐rift epimet. rcksBasement

? ?

Dole/Hornudji

Pindiga‐GombeArea NBT

Bima Hill AreaNBT

Chad (Termit) BasinChad/Niger Republics

Continental(Alluvial/Braided/Fluvial/Lacustrine)

Transitional – Marine ‐ Transitional

Pre‐Bima

Lower Bim

a(B1)

Middle Bima(B2)

Upp

er Bim

a(B3)

YoldeFm

3000

2700

2400

2100

1800

1500

1200

900

600

300

0m

YoldeFm

Upp

er & Low

erBima(B2&

B3)

Lower Bim

a(B1)

& ?Pre‐Bima)

Pind

igaFm

GombeFm

Kerri KerriFm

20‐500

30‐1100

300‐900

300‐1500

300‐1700

200‐1000

300‐2500



Sokor)

Madama/GresMassif

Yogou/Agadem

Donga/Zoo Baba

Sedigi/Alaniara

K1/Tefidet

HolocenePleistocene

Pliocene

Miocene

Oligocene

Eocene

Palaeocene

Maastrichtian

Campanian

Santonian

Coniacian

TuronianCenomanian

Lower Cretaceou

s (Barria

sian

–Albian

)

Jurassic& Older

Pre‐Cambrian

Thickness(m)


? ?

Dole/Hornudji


Bima Hill AreaNBT




Sant. Unc.

Pre‐Bima

Lower Bim

a(B1)

Middle Bima(B2)

Upp

er Bim

a(B3)

YoldeFm

3000

2700

2400

2100

1800

1500

1200

900

600

300

0m

YoldeFm

Upp

er & Low

erBima(B2&

B3)

Lower Bim

a(B1)

& ?Pre‐Bima)

Pind

igaFm

GombeFm

Kerri KerriFm

20‐500

30‐1100

300‐900

300‐1500

300‐1700

200‐1000

300‐2500



Sokor)

Madama/GresMassif

Yogou/Agadem

Donga/Zoo Baba

Sedigi/Alaniara

K1/Tefidet

HolocenePleistocene

Pliocene

Miocene

Oligocene

Eocene

Palaeocene

Maastrichtian

Campanian

Santonian

Coniacian

TuronianCenomanian

Lower Cretaceou

s (Barria

sian

–Albian

)

Jurassic& Older

Pre‐Cambrian

Thickness(m)


? ?

Dole/Hornudji


Bima Hill AreaNBT




Sant. Unc.

Chad (Bornu) Basin

Correlation Across Contiguous Basins & New Stratigraphic Proposition of the Chad (Bornu)

Basin

Pre‐Bima

Lower Bim

a(B1)

Middle Bima(B2)

Upp

er Bim

a(B3)

YoldeFm

3000

2700

2400

2100

1800

1500

1200

900

600

300

0m

YoldeFm

Upp

er & Low

erBima(B2&

B3)

Lower Bim

a(B1)

& ?Pre‐Bima)

Pind

igaFm

GombeFm

Kerri KerriFm

20‐500

30‐1100

300‐900

300‐1500

300‐1700

200‐1000

300‐2500



Sokor)

Madama/GresMassif

Yogou/Agadem

Donga/Zoo Baba

Sedigi/Alaniara

K1/Tefidet

HolocenePleistocene

Pliocene

Miocene

Oligocene

Eocene

Palaeocene

Maastrichtian

Campanian

Santonian

Coniacian

TuronianCenomanian

Lower Cretaceou

s (Barria

sian

–Albian

)

Jurassic& Older

Pre‐Cambrian

Thickness(m)


? ?

Dole/Hornudji

Sant. Unc.


Bima Hill AreaNBT


Gubio Sw‐1 Well

Chad (Bornu) Basin


Transit. Marine

?Lac. ‐ Fluvial –Alluvial Plain

Lac. ‐ Fluvial

New Stratigraphic Proposition….. Contd.

Typical seismic section showing various stratigraphic intervals in Bornu Basin. Note the unconformitybeneath the Kerri-Kerri Formation (from Avbovbo et al., 1986).

New Stratigraphic Proposition….. Contd.Yola Gongola

NORTHERN BENUETROUGH

CHAD (BORNU)BASIN

TERMIT BASINAGE

Quaternary

Pliocene

Miocene

Oligocene

Eocene

Palaeocene

Maastrichtian

Campanian

Santonian

Coniacian

Turonian

Cenomanian

Albian –?Upper Jurassic

Pre‐Cambrian

? ?

Dole/Hornudji

Sokor 2 (Argile de Sokor)

Sokor 1 (Alternance de Sokor)

Madama/Gres Massif

Serie de Yogou/Agadem

Donga/Zoo Baba

Sedigi/Alaniara

K1/TefidetBima

Yolde

Basement

Pind

iga

Kanawa

Dumbu

lwa/

Deba

Fulani/

Gulan

i

Gongila

FikaFika

GombeGombe

Kerri KerriKerri Kerri

Chad

LamjaNumanhaSekuliyeJessuDukul

Volcanics& IntrusivesVolcanics

Unconformity

Volcanics

Schematic Tectono‐Depositional Model of Gongola & Chad (Bornu) Basins & Its Implication to Petroleum Potentials

50 km

Chad Formation

Gombe Formation

Yolde FormationKerri Kerri Formation

Fika Shales

Sandstone

Shale

LimestonePind

iga/Gon

gila

Form

ation

Upper & MiddleBima Sandstone

Lower Bim

aSand

ston

e

Sandstone

Lacustrine Shale

Alluvial Sandstone/Fanglomerates

Basement

Unconformity

Fault

SW NECHAD (BORNU) BASINGONGOLA BASIN0m

~7100m

Modified from Saugy (1987)

CHAD BASIN

NEOG. – QUAT.VOLCANICS

BENUE TROUGHBASIN

BASEMENT

DEPTH TO BASEMENT

>5000m

3000-5000m

1000mCONTOUR

WELLS1 Gubio SW-12 Wadi-13 Kinasar-14 Kanadi-15 Albarka-16 Mbeji-17 Kemar-1

23

4

5 6

NIGER

CHAD

CAMEROON

1

100km

7

NE

SW

Hypothetical section from Gongola Basin – Chad (Bornu) Basin

50 km

Chad Formation

Gombe Formation

Yolde FormationKerri Kerri Formation

Fika Shales

Sandstone

Shale

LimestonePind

iga/Gon

gila

Form

ation

Upper & MiddleBima Sandstone

Lower Bim

aSand

ston

e

Sandstone

Lacustrine Shale

Alluvial Sandstone/Fanglomerates

Basement

Unconformity

Fault

SW NECHAD (BORNU) BASINGONGOLA BASIN0m

~7100m

NE

SW

Hypothetical section from Gongola Basin – Chad (Bornu) Basin

• Migrationalpathways will be both vertical & lateral along unconformities & faults

Summary The strat. of the Chad (Bornu) Basin was mainly developed from sub‐crop data

The basin developed as part of the WCARS and is bounded by the Gongola Basin (NBT) to the SW & Termit Basin (Chad & Niger Republics) to the NE; therefore its strat. is comparative to such contiguous basins

To this effect, a new stratigraphy was developed for the basin, such that: Cen. shallow marine so‐called “Bima Sandst” (including the Bima Shale Member, Bima Sand Member and pre‐Bima of

Simon‐Robertson Report, 1991) is the correlative Yolde Fm in the Gongola Basin and Sedigi/Alianara Fms in the Termit Basin The Fika Shale is Campanian – Maastr. and unconformable & correlatably conformable on the Gongila Fm at uplifted high &

deeper basinal areas respectively Maastr. – Palaeoc. ‐ ? Oligoc. sediments (Gombe & Kerri Kerri Fms in the Gongola Basin; Madama, Sokor 1 & 2 in the Termit

Basin; or their equivalents) were considered deposited in the basin, but subsequently eroded by the end Maastr., end Eocene, & early Miocene events especially at the Central part of the basin, such that Miocene – Pleistocene sediments (Chad Formation) unconformably rest on the Campanian – Maastr. Fika Shale as observed in the boreholes

HC kitchen is expected at the central part of the basin (sub‐basins) & reservoir facies are expected at the flanks of uplifted highs

Traps are both stratigraphic and structural

Migrational pathways are vertical and lateral along mostly faults and unconformities

Basement reservoirs & seal pair plays are possible

Thank You & God Bless

“Where oil is first found, in the finalanalysis, is in the minds of men & women” (Pratt, 1952)

“Explorers are optimistic, positive thinkers (negative‐thinking people do not find oil & gas)” – Norman Foster

A RE-THINK ON THE

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