Insights into the Geology and Prospectivity of the

Joint Development Zone (JDZ)Christine Roche New Ventures Africa PGS

Executive summary – JDZ MC3D prospectivity review

3. Quantative Interpretation work shows that hydrocarbon

charge of reservoirs can be identified & calibrated.

4. The study shows that there are undrilled leads calibrated

to 8 drilled wells

2. Well log and seismic interpretation show pro-delta

reservoir facies within structural and stratigraphic traps.

1. PGS have a comprehensive dataset within the JDZ.

MC3D

Well CPI’s

Mud Logs

Gas Logs

Biostrat

Cuttings

Checkshots

Well Reports

Deviation Data

The JDZ and the JDA

In 2001 a treaty was signed between Nigeria and São Tomé & Principé which defined the Joint Development Zone (JDZ).

The Joint Development Authority (JDA) was established to manage the activities relating to exploration for and exploitation of the resources of the JDZ, including the issuance of permits and licenses.

PetroView

Joint

Development

Zone

Wells and Fields

4

Malanza-1X

Addax (2009), Gas Well,

TD = 4172 m

The well targeted nine reservoir sand intervals of which two

contained biogenic methane. The well was plugged and abandoned.

Kina-1XR

Addax (2009), Gas Well

TD = 3750 m

The well encountered non commercial quantities of gas from multiple reservoir sands. The well

was plugged and abandoned

Lemba-1X

Addax (2009), Gas Shows

TD = 3758 m

The well targeted 8 reservoir sand intervals of which two contained

methane gas of biogenic origin and others were water bearing. The well

was plugged and abandoned.

Oki East-1X

Addax (2009), Gas Well

TD = 3840 m

Multiple gas bearing deep marine turbiditic sands have been intersected by

this well. The well was plugged and abandoned

Obo-2

Total SA (2012), Oil and Gas Well, TD = 4270m

The well encountered oil and gas pay and have been plugged and

abandoned as non-commercial well.

Obo-1

Chevron Texaco JDZ (2006), Oil & Gas Well, TD = 4600m

The well found a cumulative total of at least 45m of net hydrocarbons in multiple

stacked reservoirs in a toe thrust structure. It has been plugged and abandoned as a non commercial

discovery.

Enitimi-1

Total SA (2012), Oil and Gas Well, TD = 3394 m

Total has plugged and abandoned this well as a non-commercial oil

discovery.

Bomu-1X

Sinopec (2009), Gas Well

TD = 3580 m

Bomu-1 well was drilled to evaluate the potential for commercial

discovery. It encountered gas shows

Regional Geology

Niger Delta tectonic setting

PGS MC3D

Thrusting in JDZ study area

JDZ – MC3D

• JDZ lies on 2 depobelts - Shale swelling and Frontal toe trust zones

• The Shale Swelling Zone is typically associated with E-W trending toe thrusts,

apparent within the Agbada Formation and detaching within the Akata mobile

shales

• Akata shales have been injected up the fault planes isolating fault blocks

• The Frontal Toe Trust Zone is associated with NE–SW fault trends controlled by

thrusting to the north

25 km

Limit of Frontal Toe

Thrust Zone

Limit of

Shale

Swelling

Zone

Thrusting

from north

Thrusting from

north-east

Regional stratigraphy of the Niger Delta

The Tertiary section of the Niger Delta is divided into 3 diachronous formations, representative of broad

depositional setting:

• Benin Formation – representative of alluvial deposits

• Agbada Formation – representative of deltaic deposits

• Akata Formation – representative of deep water muds

The area of the JDZ MC3D dataset is located in a delta front to deep water setting and is dominated by

Agbada Formation delta front deposits that is detached from underlying Akata shales

From Freddy et al., 2005

Setting of

JDZ MC3D

Detachment Level

Delta frontDeep water

Delta topDelta front

JDZ

PGS Data Package

Available data package

Bomu-1X(2009)

Enitimi-1(2012)

Oki East-1X(2009)

Obo-2(2012)

Obo-1(2006)

Lemba-1X(2009)

Kina-1XR(2009)

Malanza-1X(2009)

PGS MultiClient 3D data PGS MultiClient 3D MegaSurveyPGS MultiClient 2D data

Vitrinite

reflectance

Pore

pressure data

Operator

mud logs

Formation

evaluation

logs

Biostrat

data

Bottom hole

temperature

MWD logs

Velocity

data

All well

reports

Well data available for brokerage

Well Log processing workflow for JDZ

2. Well data

cataloguing

3. Collation of

operator data

6. Workstation Ready Log

Suite (WSR)

1. Well data collection

and management

4. Well log scanning &

digitising

5. Well log QC, splicing &

environmental corrections.

Well Log interpretation workflow for JDZ

8. Sequence

stratigraphic

interpretation

10. Petrophysical

analysis (CPIs).

13. Well to seismic tie using

checkshot, VSP & synthetics

7. Lithological

interpretation

9. Depositional Environment

and Facies Interpretation

11. Reservoir fluid elastic

attribute analysis

TS

TH

ST

TS

T

SB NN4

12. Acoustic attribute to pre-

stack trace calibration

Well sequence and depositional environment interpretation – Kina-1XR

SB NN9

SB NN8

SB NN1/2

TS

TT

ST

TS

TH

ST

HS

TH

ST GAS

GAS

GAS

SB NN6/7

HS

TT

ST

M. Tortonian

Serravalian

E. Tortonian

Top Oligocene?

Top Eocene?

Lowermost Shoreface sands

Offshore Transition sands

Outer Shelf

Lowermost Shoreface sands

Offshore Transition sands

Outer Shelf

Lowermost Shoreface sands

Offshore Transition sands

Outer Shelf

SB NN4

Langhian

Outer Shelf

Lowermost Shoreface sands

Offshore Transition sands

Offshore Transition sands

Outer Shelf

GR RHOB DT Res

NPHI

SW

Biostrat

data

Operator

shows

H/C from

CPI

Gas @ 2575m,

2940m, 3120m,

3480m,

Check shot

Well does not penetrate

Akata Fmn

Well to seismic tie - Enitimi

A

A’

GR Ip Vp NEAR

c.NN7

c.NN4

c.NN9

c.NN8

c.NN5

c.NN11Enitimi Enitimi-1

Total SA (2012), Oil and Gas Well, TD = 3394 m

Four of the primary reservoirs were encountered. Only one reservoir intersected oil. Water in the deepest level at

2932 TVDSS

NN8

NN4

NN9

NN11

NN5

NN6/7

Seabed

Near Top

Tortonian

Messinian

NN11b

Top Eocene

Intra Tortonian

NN9

Top Lwr

Miocene NN4

Build and interpret sequence framework in 3D dataset

A

A’

Example time and depth structure maps

Intra Tortonian depth map with

100m contour interval

**Interval velocities have

been used in preSeis for

depth conversion

NN9

Intra Tortonian two way travel time map with

100ms contour interval

Faulting associated

with Shale Swelling

Zone

Faulting associated

with Frontal Toe Thrust

Zone

B2C

Marker D RMS amplitude +20 to +120ms

B2CB2C

Structural Lead:

Closure within a toe thrust,

very bright amplitudes at crest

Reservoir: likely to be Lower

Shoreface sands

Seal: likely to be intra-

formational TST transgressive

muds.

NN11a

NN10

NN9NN4

NN4

NN11a

NN10

NN9

OligOlig

NN11b

NN11b

Play analysis - an example of a structural lead

Bomu-1X

Sinopec (2009) Gas Well

(approx. location)

Bomu-1X

Well interpretation

R

S

S N W E

Play analysis - an example of a stratigraphic lead

Marker B RMS amplitude

+20 to +120ms Stratigraphic Lead:

Sand prone body pinching out against thrust fault.

Reservoir: likely to be Offshore Transition mass flow or Lower Shoreface

Seal: likely to be intra-formational TST transgressive muds.

B1M

B1L

NN11a

NN10

NN9

NN11b

Marker BB1L

B1M

NN11a

NN10

NN11b

1BM

Quantitative Interpretation

Reservoir analysis - quantitative interpretation workflow

Water-wet

(Brine)

sands

Ip (rel)

VpV

s (

rel)

Elastic attribute cross-plot

Hydrocarbon

sands

shales

Rock physics shows elastic attributes can

discriminate shale – brine sand – HC sand

Well log elastic attributes discriminate lithology &

fluid (shale – brine sand – HC sand). This pattern

is consistent with the seismic elastic attributes

(Ip and Vp/Vs)

Seismic sections of elastic attributes clearly show the

difference between – shale, brine sand & HC sand

with strong changes at hydrocarbon water contacts

With such a clear pattern in elastic attributes we can auto-detect areas of specific values (low Ip and/or

Vp/Vs) as ‘geobodies’.

These are calibrated to well log reservoir properties and identify many untested leads

We have mapped the top or base of

anomalies in leads and discoveries to

understand the relationship between HC

fill and structural closure / fill

Example well tie with seismic elastic attributes

High

Low

Ip

LOW

Vp/Vs

LOW

Ip

LOW

Vp/Vs

LOW

Gas

satCPI

Ip

absoluteRho (seismic)

Ip-rel

Vp/Vs

absoluteIp

relative

Elastic well logs

Vp/Vs

relative

seismic inversion

volume Ip-rel

Seismic inversion (relative)Well log

petrophysics

(seismic)

Vp/Vs-rel

Gas in

CPI

Gas in

CPI

Gas sand

seen in

seismic

inversion

volume

Minor

gas in

CPI

Minor

gas in

CPI

3D view of wells and leads: Geo-bodies extracted from Ip & Vp/Vs

Lemba Kina

MalanzaObo-1

Obo-2 EnitimiBomu

Oki East

Basin Modelling

23

Sub Akata Prospectivity

PGS Discovery Webinar – Deeper Insight into the Niger Delta Tectonic domains through southern Niger Delta

Zone of outer

thrusting

Zone of minor

thrusting

Zone of shale

diapirism

Late Cretaceous

Oceanic Crust

Danian

Thrust onset

Late thrust

Akata Shale

Thrusted conformable layer

S N

PGS Discovery Webinar – Deeper Insight into the Niger Delta The South-eastern front – sub-Akata opportunities

26

Cretaceous play

Sub Akata play

Top Akata

shale

Sub Akata play

Cretaceous play

Conclusions

• JDZ is significant hydrocarbon prone area. All the elements

of working petroleum system have been identified and

evaluated

• 8 wells have been drilled with both oil and gas discovered

• Depositional sequence interpretation shows that reservoirs

are lowermost shoreface sands and pro-delta mass-flow

sands (channels, fans and lobes)

• The sub-Akata section may be provide a secondary

petroleum system

• Quantitative interpretation is an important tool for derisking

• Opportunities to develop discoveries and drill stacked

reservoirs

Thank You

Visit us on Booth 13 in International Pavillion

Email: amme.info@pgs.com

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