A new 3D seismic coverage Southwest of the Troll Field ...€¦ · A new 3D seismic coverage...
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A new 3D seismic coverage Southwest of the Troll Field: Possible 4D baseline survey for CO 2 injection in the Johansen Formation ? Jensen, L. , Alsaker, E. , Diesen, M. , Johansen, W.T., Mathiassen, O.M. , Ro, H.E. , & Vetaas, M. Production Geoscience 2009 Conference November 3-4, at NPD Stavanger
Transcript of A new 3D seismic coverage Southwest of the Troll Field ...€¦ · A new 3D seismic coverage...
A new 3D seismic coverage Southwest of the
Troll Field: Possible 4D baseline survey for CO2
injection in the Johansen Formation ?
Jensen, L. , Alsaker, E. , Diesen, M. , Johansen, W.T.,
Mathiassen, O.M. , Ro, H.E. , & Vetaas, M.
Production Geoscience 2009 Conference
November 3-4, at NPD Stavanger
Presentation Outline
Introduction / background for project
Data Acquisition & Data Processing
Results / Mapping of the Johansen Formation in
Block 31/5
4D Sensitivity Analysis
Conclusions / Recommendations
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Introduction / background for project
- Geological setting
- Some initial findings
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Project background
The NPD conducted initial works & mapping in search for locations
in NOCS for possible CO2 storage (Kårstø & Mongstad)
Troll – Johansen (Block 31/5, open acreage) was identified as a
suited location (in parallel with a number of other alternatives)
Further works and mapping for the Troll – Johansen was carried
out – along with acquisition of 3D seismic data in Block 31/5
In the Spring of 2009 following the outcome of “konseptvalg 2008”
it was decided that GASSNOVA SF should continue the work &
projects that the NPD had initiated – in order to further mature the
selection of site(s) for permanent CO2 storage
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– end 2007
2008 –
Mid 2009
Mid 2009 –
Johansen Formation & 3D Survey outline
a) Geol. Cross-section showing the relation between the Lower Jurassic Johansen Fm. in relation to the overlying
Sognefjord & Fensfjord Fm. from which the Troll Field produces. The interval between these two “targets” is approx. 500m
in this area, consisting of several sealing shale layers.
b) Index map of the 3D survey outline (NOCS Block 31/5) in relation to the surrounding Troll Field to the East & North.
The thick white dotted line indicates the approx. location of the Geo-profile in a).
Dunlin
Fensfjord
Krossfjord
Brent (Ness)
Brent (Etive)
Johansen
Sognefjord
a) b)
31/6-1
3D
seismic
Survey
outlineScale:
20 Km
31/2-5
31/5-2
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Well info – overview cpi logs
31/5-2
”Res
ervoir”
”Seal”
Sca
le:
100m
70m
31/2-5
”Res
ervoir”
”Seal”
Dra
ke
31/6-1
”Seal”
”Res
ervoir”
80m
Dra
ke
Co
ok
- VIP: Johansen Fm. is non-calcareous aquifer
- I.e. good water bearing reservoir with seal
AND so deep placed that CO2 is beyond critical phase
2000m
2200m
2200m
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1 year 50 years 110 years
Result from SINTEF 2007 simulation
[ This simulation was based on knowledge as before a fault-seal study
was performed by Badley’s (2008) and the update mapping based on
new 3D seismic ]
- Yearly injection-rate 3.0 MT CO2
SINTEF has assumed a "worst case scenario” with max. lateral communication
via sand-to-sand contact in the main fault-zone. The conclusion was that it would
take at least 150 years before the CO2 would reach the Troll reservoir.
Pre-study,Semi-regional seismic interpretation
3D seismic covering the Troll Field,
the remaining study area covered by
2D seismic
Difficult to map the details and limit of
the Johansen Fm. towards South and
Southeast based only on 2D seismic
In 2008, a new 3D-seismic survey was
acquired and processed, providing:
Improved reservoir mapping
Better control of faults /
fractures
4D Base-line survey (= T0)
Optimal placement of verification
well
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Data Acquisition & Data Processing
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Seismic Data Acquisition
Coverage Plot, Far-mids.
Parameters:
Survey vessel: PGS RAMFORM CHALLENGER
Period: 4 - 17 Sept. 2008
10 streamers @ nominal 7.0 m depth
(1 streamer overlap to next pass = “4D Ready”)
Active streamer(s) length – 3000 m
(Need of this offset 80-85% at 2,5 sec. TWT)
Flip-flop shooting, 12.5 m pop interval – 60 fold
4096 ms recording length
Survey volume:
300 km2 FF; infill was 3.4 %
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Inline 1221: Stack before De-multiple, no SRME (& no Radon)
Inline 1221: PSTM Stack
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Results / Mapping of the Johansen Formation in Block 31/5
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Inline 1207
Top Draupne
Top
Brent
Top Drake
Top Cook
Top Johansen
Top Statfjord
Base Statfjord
Top Sognefjord
Top Shetland
W E11/03/2016 13
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W E
Top Draupne
Top
Brent
Top Drake
Top Cook
Top Johansen
Top Statfjord
Base Statfjord
Top Shetland
Top Sognefjord
Inline 1687
14
Max. throw at Top Cook / Johansen level:
Approx. 40-50 ms TWT = 50-60 m (vel. 2500 m/s)
Then OK, since Seal = “Drake” is 70-80m
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N S
Top Draupne
Top Brent
Top Drake
Top Cook
Top Johansen
Top Statfjord
Base Statfjord
Top Sognefjord
Top Shetland
Crossline 1399
15
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Top Cook Time-structure4
00
0 m
16
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Top Johansen Time-structure
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Time slice at 2300 ms
Time Slice at 2300 ms, close to the ’zone of interest’
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Johansen Relative Acoustic Impedance (RMS Amplitude)
Petrel Tool: Estimated relative acoustic impedance is calculated by integrating the trace,
then passing the result through a high-pass Butterworth filter
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Thin Slab Slice (100ms) at 2220ms
Channel!
‘Thin Slab Slice’ of 100 ms width centered around 2220 ms – providing a very good picture of the fractures / fault
pattern at the ‘interest zone’. Also observe that a meandering channel to the South in the survey area is revealed.
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Shallow Gas
@
approximately
565 m MD
Area
covered
by
Shallow
Gas
Time-slice @700 msec
Inline
1911
Base Quaternary
Inline 1911
4D Sensitivity
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4D Sensitivity Study
Purpose: To estimate the 4D effect that can be expected after injection of CO2
in the Johansen Fm.
The analysis was done on 3 wells 31/6-1, 31/5-2 and 31/2-5 using Vp and
density logs.
Since the wells were outside the area of the interest, the Johansen formation
was on the different depth than required. Therefore, the wells had to be shifted
to the modelling depth prior to the 4D analysis (2000m +500m for well 31/6-1).
The 4D modelling itself was done for 4 different scenarios:
- CO2 saturation 90%, CO2 thicknesses of 40, 25,10 & 5m
Main Modelling Steps:
• Moving well to the correct depth
• Fluid substitution scenarios
• Synthetic creation (cmp gathers)
• 4D analysis
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Top Johansen Depth Map
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Well 31/6-1 (target at ~2500m)
Lithology Vp Vs Density Offset gather Angle gather
Original logs; FRM logs
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Original logs; FRM logs
Well 31/6-1 (~ 2500m) after fluid substitution – CO2 thickness 10m
Lithology Vp Vs Density Offset gather Angle gather
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Lithology Vp Vs Density Offset gather Angle gather
Well 31/6-1 (~2500m) after fluid substitution – CO2 thickness 25m
Original logs; FRM logs
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Original logs; FRM logs
Lithology Vp Vs Density Offset gather Angle gather
Well 31/6-1 (~2500m) after fluid substitution – CO2 thickness 40m
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Well 31/6-1 (at 2500m) – 4D differences (random noise added) before & after CO2 injection (Sg=90%; H=5m vs 10m)
in situ Diff. H=5m Diff. H=10m
Top Sand
Top Johansen
Johansen_2
Johansen_1
Result from 4D forw. modeling. This was done by using the acoustic impedance from neighboring Block 31/6-1well and “projecting” the logs at +500 m depth (in order to best simulate conditions at Block 31/5).A ‘realistic’ CO2 saturation of 90% was used and several thicknesses were modeled.Herein, the expected seismic 4D responses for CO2 column thickness of 5 & 10 meters are shown.
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Conclusions / Recommendations
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Conclusions / Recommendations
A 3D dataset of good quality has been obtained
- in order to make a decision for a pilot well location
T1 monitor survey should be acquired after circa 2 years
of CO2 injection
[ based on assumed flow-rate of 3.0Mill.T per year ]
In general: We can capitalize on the experiences gained
for hydrocarbon reservoirs - and use very similar
methodologies in order to best manage CO2 storage
projects
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Acknowledgements
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MISC SUBJECT:”Drag folds” along the mainBoundaring fault towardsTroll East
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Troll East main fault
Johansen level
Top Draupne
Top
Brent
Top Drake
Top Cook
Top Johansen
Top Statfjord
Base Statfjord
Top Sognefjord
Top Shetland
N S
Crossline 2951
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Troll East main fault
Johansen levelN S
Top Draupne
Top Brent
Top Drake
Top Cook
Top Johansen
Top Statfjord
Base Statfjord
Top Sognefjord
Top Shetland
Crossline 2980
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Drag effects along Troll East Border Fault
Troll East
Troll EastCrossline 2951
Timeslice 1878 ms
Timeslice 1988 ms
Inline 1399
Inline 1399
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Top Cook Time-structure4
00
0 m
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Time slice at 2300 ms
Time Slice at 2300 ms, close to the ’zone of interest’
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Johansen Relative Acoustic Impedance (RMS Amplitude)
Petrel Tool: Estimated relative acoustic impedance is calculated by integrating the trace,
then passing the result through a high-pass Butterworth filter
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Thin Slab Slice (100ms) at 2220ms
Channel!
‘Thin Slab Slice’ of 100 ms width centered around 2220 ms – providing a very good picture of the fractures / fault
pattern at the ‘interest zone’. Also observe that a meandering channel to the South in the survey area is revealed.
4011/03/2016
