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
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