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44--D Microgravity D Microgravity
and Fluid Movement and Fluid Movement
in Reservoir in Reservoir
Eko Widianto
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GeologistsDepositional Environment
PetrographyPaleontology
GeophysicistsInterpret Seismic and Gravity Surveys todefine of Structure and continuity of reservoir and Aquifer size
EngineersAnalyze data on Logs,Cores, Fluid Samples,
And Well Tests
Oil and Gas in PlaceReserve, RateAquifer Size
Communication among team members during appraisal phase
Appraisal PhaseAppraisal Phase
Data Available:1. Seismic Lines2. Logs, Cores, Fluid samples & well tests on 2 wells
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GeologistsCorrelate Zones,
Continuity of Pay & shales,Structure Maps,
Sections Isopach Maps
GeophysicistsInterpret fine-grade
Seismic data for structure,Continuity of zones,
Faults and Aquifer size
Optimum DepletionPlan, Locationand number ofPlatforms &
wells
Communication among team members during planning phase
Planning PhasePlanning Phase
EngineersDetail Reservoir
Description,
Reservoir Simulation,
Well & Platform
Constraint,
Economic
Data Available:1. Fine-grade Seismic Lines2. Logs on 4 to 10 wells3. Cores & well tests on 3 or 4 wells
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GeologistsGeophysicistsContinuity of pay distribution and
dimensions of shales
Production Engineer
Well Bore HydraulicOptimum completion
Methods
ReservoirEngineers
Computer studies of wellBehavior, Update
Studies of Reservoir Behavior
Completion & WorkoverPolicies, OptimumDistribution ofInjection & Produces fluids
Communication among team members during development phase
Development Development
PhasePhase
Data Available:1. Fine-grade Seismic Lines 3. Cores on 25% of wells2. Logs on all wells 4. Well tests on 3 or 4 wells
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GeologistsGeophysicistsUpdate Cross Sections,Analyze Workovers
Production Engineer
Analyze Well Surveysto locate gas and water
entry,Workovers wells
ReservoirEngineers
Analyze Performance,Update Model Studies,Analyze Workovers
Revise injection plan to improveperformance
Communication among team members during reservoir management phase
Reservoir Reservoir
Management Management
PhasePhase
Data Available:1. Pressure survey 3. Contact Logs2. Gas-oil & Water-oil Ratios 4. Well bore surveys
Fluid Movement in Reservoir
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4D Microgravity caused by:
1. Subsurface fluid dynamics
2. Season change
3. Subsidence
4. Pressure change
5. Topographic change
4D microgravity anomaly response is very small
(orde < 100 microGal)
Need good survey planning
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Integration of Disparate Data (Kinds &
Scales)
Cased Hole Logs
Production Histories
Pressures & Temperatures
4-D Seismic Monitoring
Gravity Monitoring
Borehole Seismics
Remote Sensing
4D Reservoir Monitoring
(x,y,z,t)
A Paradigm Shift in Production ManagementScience & Technology Components
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Surface gravity changes reflect underground
mass redistribution caused by production and
re-injection of hydrocarbon fluids
Precise measurement and analysis of gravity
changes can thereby help reveal changes in
reservoir conditions
establish a systematic procedure for micro-
gravity monitoring of operating Hydrocarbon
fields
Gravity Monitoring
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1. OPTIMIZING Wells Production (Existing)
2. Production Wells PRESSURE MAINTENANCE
3. PATTERN WATERFLOODING in Reservoir
4. ADDING / SHUT-OFF / MOVING
Injection Well (existing)
5. RE-OPENING of Potential Layer
6. ETC
PRODUCTION IMPROVEMENT OF
HYDROCARBON FIELD :
WHY 4DWHY 4DWHY 4DWHY 4D----GRAVITY ANOMALY GRAVITY ANOMALY GRAVITY ANOMALY GRAVITY ANOMALY
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UNIT OF GRAVITY
After Galileo :
1 ms-2 = 106 ms-2
= 109 nms-2
Gravity g(x,y,z)
is acceleration in System International dUnites (SI) is ms-2
1 Gal = 1 cms-2
= 10-2 ms-2 (SI)
Gravity anomaly :
mGal (in exploration) 1 mGal = 10-3 Gal
Gal (in 4D survey) 1 Gal = 10-3 mGal
= 10-6 Gal
= 10-8 ms-2 (SI) called as 4D microgravity
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-Decrease in Mass
-Pressure Decrease
- Secondary gas
cap
Schematic Map and Profile
(time-lapse microgravity anomaly
Before Production After Production
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Schematic Map and Profile
( Time-Lapse microgravity anomaly)
Before Injection After Injection
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Time lapse microgravity anomaly after water injection 2.400.000 ton.
Max. Anomaly: 12 Gal
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500 m
100m
Permukaan tanah
Reservoir Minyak
B
Model reservoir sederhana
(porosity 30%, minyak 0.88 gr/cc)
Respon (anomali) microgravity
reservoir minyak (blm diinjeksi)
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Respon microgravity setelah
reservoir diinjeksi fluida 75.000 m3
Model reservoir dg porosity 30%,
minyak 0.88 gr/cc
Distribusi fluida injeksi
( = 0.252 gr/cc) dlm reservoir
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Respon microgravity setelah
reservoir diinjeksi fluida 675.000 m3 .
(reservoir dg porosity 30% dan
minyak 0.88 gr/cc)
Distribusi fluida injeksi dlm reservoir
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Anomali microgravity 4D setelah
injeksi fluida 75.000 meter kubik
Anomali microgravity 4D
setelah injeksi fluida 675.000
meter kubik
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Data - data simulasi :
a. Reservoir 1800 x 1800 x 100 m3
b. Porosity reservoir 30%
c. Dentitas minyak 0.88 gr/cc
d. Densitas fluida injeksi 0.252 gr/cc
e. Jumlah minyak keluar 30.000
barrel/day
f. Jumlah fluida injeksi 30.000
barrel/day
0.00 200.00 400.00 600.00 800.00 1000.00 1200.00 1400.00 1600.00 1800.000.00
200.00
400.00
600.00
800.00
1000.00
1200.00
1400.00
1600.00
1800.00
Distribusi sumur injeksi
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Respon microgravity
reservoir sebelum injeksi
(base line)
Respon microgravity reservoir
setelah injeksi 1 bulan
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Respon microgravity reservoir
sebelum injeksi fluida (base line)
Respon microgravity reservoir
setelah injeksi fluida 3 bulan
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Anomali microgravity 4D setelah
injeksi 1 bulan
Anomali microgravity 4D injeksi
3 bulan
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CASE STUDY
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TUJUAN
Identifikasi pergerakan air injeksi dari anomali
4D microgravity dan hasil dekonvolusi () dan
inversinya (Saturasi air injeksi).
Perilaku reservoir dalam proses produksi
( P, mass decrease & secondary gas cap)
Deliniasi sesar dan perilakunya terhadap
pergerakan air injeksi
(Dikomplemenkan dengan hasil-hasil studi lainya).
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Akuisisi I
Akuisisi II Akuisisi III
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Gravity value
Rainfall
Relationship between rain fall and observed microgravity
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SOURCE OF
4D MICRO-GRAVITY ANOMALY
Injection Water
Pressure Increase (+) g(+)
Decrease of Mass
Pressure Decrease (-) g(-)
Secondary gas cap
Wet & dry season (-) g(-)
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DATA PROCESSING
-Forward Modeling Subsurface Bodies
-Deconvolution Density Contrast Map
-Inversion Apparent Saturation
To identify source of microgravity anomaly :
1. Injection water and Pressure Increase
2. Secondary gas cap, mass and pressure decrease
3. Decrease of Surface water
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gobs akuisisi I (Jan03) akuisisi II (Mei03) akuisisi III (Sept03)
gobs Lokal
(relatif pada Base station)
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4D Microgravity Anomaly
of Y area
Mei-Jan03 Sept-Jan03 Sept-Mei03
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MICRO-GRAVITY ANOMALY OF Y
FOR SEPTEMBER-MEI 2003 PERIOD
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Microgravity Anomaly
(Sept-May 2003)
Structure of top F-sand
from well data (red)
- Estimated structure
from microgravity
anomaly (yellow)
Anomali 4D Microgravity lapangan Y periode September Mei 2003
dan struktur puncak batupasir F dari data sumur (merah) serta dari 4D data (kuning)
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Anomali Microgravity Sept-Mei03
Fault
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Density Contrast Map of Sep-Mei03 Period
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Apparent Saturation of Sep-Mei03 Period
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Struktur Seismik 2D
(lama, 1980)
Struktur Data sumur
(baru)4D Microgravity
Komparasi Struktur
(latar belakang : anomali microgravity Mei-Jan03)
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Subsurface model of Sep-Mei03
microgravity anomaly
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2. Dari hasil diatas dan penampang model :- Sesar Baratlaut-tenggara Sealing
- Sesar Timurlaut-Baratdaya partially Sealing or bocor(?)
KESIMPULAN
1. Korelasi Anomali 4D Microgravity & top struktur :- Pergerakan air injeksi dikontrol oleh sesar
Timurlaut-Baratdaya dan Baratlaut-Tenggara
3. Sesar sbg pembatas dan pergerakan awal :- 4D Microgravity deleniasi sesar (gambar berikut)
- Korelasi dg sesar dari data sumur dan seismik 2D
Sesar 4D microgravity close to sesar data sumur
4. Dari hasil 4D microgravity, reservoirnya :
- Kompartementasi oleh sesar- Didukung data tekanan
