How to get the most out of your Oil Rim Reservoirs? Reservoir management and hydrocarbon recovery enhancement enhanceme nt initiatives
Rahim Masoudi Principal Reservoir Engineer
1
Outline: Oil Rim
definition/concept/Challenges definition/concept/Challenges technologies/success ess Guidelines/best practices/key technologies/succ factors Reservoir and business management and exploitation strategies Successful field application and examples Closing Remarks
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Outline: Oil Rim
definition/concept/Challenges definition/concept/Challenges technologies/success ess Guidelines/best practices/key technologies/succ factors Reservoir and business management and exploitation strategies Successful field application and examples Closing Remarks
2
Oil Rim Opportunity and Headache! •Limited Thickness •Overlain by Gas Cap •Underlain by Aquifer
3
Forces Balance Mechanism: Gas Cap Expansion
•Preservation of Reservoir Energy •Maximizing the hydrocarbon recovery
Withdrawal Aquifer Drive Indicates regions of high flow into the well bore
Indicates regions of low flow into the well bore
4
Technical Challenge Challenges: s: • • • • • •
Water/Gas Coning and Break-through Spread Out Resources Complicated Production Mechanism Transition and Invasion Zones Oil Smearing Low Recovery Factor (<18%)
Business Challenges: • Diff ffeerent focus for the host company and th thee operato tor r • Narrow window of opportunity for “Oil rim” development • Early gas commitment vs. oil rim IOR development • Expensive Field Development and marginal economy
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Oil Recovery Factor: Main Affecting Parameters •Oil Thickness •Permeability • Aquifer support •Kv/Kh •Gas Cap Size •Viscosity and mobility •Sor, Pc, Kr •Well Placement •Production Strategy •GIGP •Reservoir well Contact •HW vs VW
Permeability and Thickness effect
Aquifer effect
6
Oil Recovery Factor: Main Affecting Parameters (Cont.) Oil viscosity effect
Kv/Kh effect
Gas cap size effect
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Available Screening Tools Traffic Light Guideline O i l Co l u m n s i z e
< 30 ft
30-70 ft
Gas cap size
m >7 and/or
m>2 and/or
M<=2 and /or
FGIIP > 1 TSCF
FGIIP > 200 BSCF
FGIIP <= 200 BSCF
Perm < 500 mD
Perm 500-1000 m D
Perm > 1000 m D
Visc > 1cP
Vi s c > 1 c P
Vi s c < 1 c P
Weak, <25% of total
Mid, ~50% of total
Strong , >70% of total
drive
drive
drive
Comp lex geometry
Complex geometry
Simple geometry
Large dip
Small dip
None or small dip
uncertainty
uncertainty
uncertainty
Mobility
Aquifer Strength Reservoir Geometry/Dip
> 70 f t
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Available Screening Tools
Gas r o t c a F M
Concurrent Oil & Gas
Oil and then Gas
Rim Thickness [ft] Source : SPE 128603
Development Strategy
9
Available Screening Tool: Shortcomings •Successful development in: Thickness < 30 ft K < 375 mD •Not in line with the guide line •4 to 10 m oil column development
Thickness <30 ft
r o t c a F M
Rim Thickness [ft] Source : C&C Reservoir and IHS Energy y c n e u q e r F
•Technical Initiatives •Technology Roles
Permeability, mD 10
Oil Rim Development Success Factors Phasing development to understand the reservoir/well behaviors
Robust geological understanding and input rock/fluid data
Proactive real time reservoir management & monitoring (PLT, Tracer, PDG, etc.)
Innovative Technical Initiatives (force balancing efforts, dual smart comp, multi-zone production with FCV, etc.)
Well/completion design/type/length/ offset
Holistic and Integrated development concept Adequate and reliable simulation/prediction (Grid, CTZ, HZ well, smart comp.,etc.)
Transition Zone Characterization and modeling
New well technology applications (long HZ, multi
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Production/Depletion Strategy Gas Cap Blowdown
-Early Gas prod. -Oil prod. Ignored! -Oil smearing concern -Low oil RF
Sequential Development
-Early oil prod. -Gas come later -Commitment concerns -Different contractual interest -Higher oil/gas RF
Concurrent Development
Swing Development
-Early oil and gas prod. -Limited gas prod. -Up to 10% of the GIIP per annual -Might suit to both operator and host company interest -Lower oil RF -Cyclic oil and gas prod. -Balance the energy -Suitable for reservoir with big gas cap -Lower oil RF
•The FDP, well design and philosophy, RMP is highly dependent on selected strategy
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Oil Rim Reservoir and Business Management
Reservoir Management
Contract & Policy
Field Development Strategy
Reservoir Energy Balance and Optimum Production
•Well type •Well length , spacing , stand off •Contact movements •GOR and production constraint •Coning, Cusping, Cresting •IOR/EOR •Gascap Blowdown •Sequential •Concurrent •Swing •Incorporated with IOR/EOR? •Robust static/dynamic models •Gas cap size • Aquifer size and extension •Driving mechanism contributions 13
Fluid Sampling, Analysis and PVT • • • • • • • •
Usually simplified! Surface sample can be misleading Both phases need to be sampled Recombined with the GIIP/STOIIP ratio Reliable fluid model is a must Modeling just Oil can be misleading on the RF evaluation Oil and Gas need to be modeled together Compositional grading and nonequilibrium concerns
(after Amyx, Bass and Whiting, 1960; courtesy of McGraw-Hill )
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Transition Zone and Oil Smearing Concerns •Saturation modeling? •Can oil rim move upward to the gas producing well? •How much is the Sor? Soi/Sor relation to be considered. •Mobile oil and displaced oil zone? •Dry oil production! Performance better than prediction!
SPE 143983 SPE 145867
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Capillary Transition Zone Flow Dynamic •Dry oil production! Performance better than prediction! •Sw Modeling: •Resistivity index and wettability effects (esp. in carbonates) •SHF from resistivity log using water wet derived n exponent can be different from that derived from drainage PC curve •This can over estimate the HC saturation above the transition zone •Saturation dependent n exponent may need to be used •Displaced Oil Zone •Imbibition curves and hysteresis effects •Pseudo Kr with artificial high immobile Sw may produce HM but can give poor prediction •How much is the Sor? Soi/Sor relation to be considered.
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Sw Determination and Modeling in Carbonates
(IPTC 14588)
Non-Archie effects
Rock Type Permeability Heterogeneity Pore size and Geometry Wettability Saturation history Hysteresis
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Sw Determination and Modeling in Carbonates
(IPTC 14588)
100
x e d n I y t i10 v i t s i s e R
1 1
10
100
Water Saturation, % pore volume
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Sw Determination and Modeling in Carbonates
(IPTC 14588)
100
x e d n I y t i v i t s i s e10 R n o i t a m r o F
1 1
10
100
Water Saturation, % pore volume
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Capillary Transition Zone Flow Dynamic (1)
SPE 77545 IPTC 10238
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Capillary Transition Zone Flow Dynamic (2)
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Capillary Transition Zone Flow Dynamic (3) SPE 143983
Rock/fluid/Sor characterization Typical Well Water cut %
0.30
0.25
r o 0.20 S
New Model Original Model
0.15
0.10 0.00
0.20
0.40
0.60
0.80
Soi
EP-F HZ well and smart comp modeling 3000
3.2E+06
3.01 2.79 2.60
2500 ) Y A D / B T S ( e t a R d o r P l i O
Typical Well Oil Prod total
2.4E+06 2000
OPR OPT OPR-MC_GI_PERM_ICD3_1 OPT-MC_GI_PERM_ICD3_1 OPR-MC_GI_MSW_1 OPT-MC_GI_MSW_1
1500
1000
) B T S 1.6E+06 ( T P O
800000 500
0 2010
2015
2020
2025
2030
0 2035
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Reservoir Modeling and Simulation
•
Girding scheme
•
Horizontal or non-horizontal corner point geometry grids
•
Horizontal grids capture the contact movement more accurately (SPE 39548)
•
Local grid refinement (LGR)
•
Finer layering scheme (SPE 93137)
•
Multi Segmented Well (MSW) approach
SPE 89755
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Modeling of Horizontal wells with smart completion Conventional modeling Hydrostatic only No
slip and friction along the well Uniform mixture density Excessive oil production in early stages
Proposed Technique Multi segmented well (MSW) model Segment topology to honor the well
path
Coupled to the reservoir model 24
Modeling of Horizontal wells with smart completion
(cont.)
MSW Capability •Reliable wellbore pressure gradient and fluid mixture properties •Proper representation of the well trajectory. • Ability to model smart completions (ICD, Inflow Control Device, ICV, Inflow Control Valve) •Coupled to the reservoir simulation equations
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Key Technologies/ Methodologies • Horizontal and Lateral Wells • Thin Column Drilling • Inflow Control Well Design • Smart Completion Design • Modeling New Technologies • Real-Time Reservoir Management • Real Time Reservoir Modeling • Improved Sweep
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Horizontal Well Basis of Design Basis of Design
Optimum Fluid Rate
Well Spacing K-10 top of Main Porosity
Distance to GOC/WOC
Lateral/perforation length Smart Completion
A-02 A-01 Gas
Phase I wells Phase II wells
East Belumut-3
A-07
1105
Perforations
A-03 st3 Belumut-2
1 5 1 1
East Belumut-1
1115
A-05 1120
A-10
A-06 1 1 2 5
Contours = 5m
Oil Water
0 1 1 1
1130
A-04
1 1 3 5
Gas Oil
Water
1 kilometer
Long Well Length
(Madsen and Abtahi- 2005)
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Horizontal Well with Smart Completion Smart Completion (ICD, ICV):
Without ICD
With ICD
•Transmit delta-P along well • Heel-to-Toe effect reduction •Higher well PI. • Better sweep efficiency.
World wide Installation Forecast!
Iron Duke Field (SPE 81107)
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ICD Minimizes Toe-Heel Effect (OTC-19172 )
World wide Installation Forecast!
Uniform Drawdown along the well
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Improve the well contact with the reservoir-1! •Brunei Shell Iron Duke Field (SPE 81107) •One H well with smart completion •Five zones in two blocks with different reservoir characteristics
(Henriksen et al., 2006) (SPE 112616)
•StatoilHydro Troll Field (SPE 112616) •Known as gas field! •110 HZ sub sea wells with 53 MLT wells •Over 13 km well contact •Up to 7 HZ branches in different zones 30
Improve the well contact with the reservoir-2!
•Total of 41 wells in 3 phases •Optimal well off set from contacts •250 m average well distance •EUR increases with well No. 31
IOR/EOR Considerations •
EOR plan integrated in FDP
•
Improve IOR through force balance
•
Minimize coning, cresting and cusping
Control fluid contact movement
Produced Gas Injection
•
•
•
GIGP Ratio
Water Injection
Injection at GOC (water fencing scheme)
Injection at WOC
Water Alternative Gas Injection
Gravity Assisted Simultaneous WAG
Lowering residual HC
Water & Gas Injection
Surfactant augmented water flood No Injection 32
Field A: Real Time RMS in a Field in Malaysia 2500
A-02 A-01 Phase I wells Phase II wells
A-07
1105
A-03 st3
0 1 1 1
1 5 1 1
A05
D / B T 1500 S , e t a R1000 l i O
A10
500 1115
A-05
1120
0 0
50
100
A-10
A-06 1 1 2 5 Contours = 5m
2000
1130
A-04
150
200
250
Days
10 1 1 3 5
1 kilometer
•
14 m oil column
•
Known as non-commercial asset!
•
Optimization of well spacing and landing
•
200 m lateral spacing for Well A05 & A10
•
4 m, 6 m and 8 m above WOC
A05
1
A10
R O 0.1 W 0.01 0.001 1
10
Days
100
1000
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Field A: Horizontal well length optimization and tracer application
•1.6 km horizontal well with ICD completion •Toe section contribution •Tracer application in the toe section •Toe flow contribution in the early stage
Tracer Test at the toe of the well
•Smart completion allows longer HZ wells •PLT is planned post WBT.
34
Field A: Horizontal well A performance with ICD post WBT
•Well-A with 1.9 km length, 4000 BPD, 5% W-cut, Np of 750 MSTB •Coil Tubing Unit clean out and PLT •Low (2.5 KBPD) and high (4.5 KBPD) rate flowing condition tested •Flow contribution from the entire wellbore
35
Horizontal well04 performance with ICD post WBT- Field A
•Well-04 with 1.6 km length, 4500 BPD, 70% W-cut, Np of 1.5 MMSTB •Coil Tubing Unit clean out and PLT •Low (2.5 KBPD) and high (4.5 KBPD) rate flowing condition tested •Flow contribution from the entire wellbore Even with ICD, there are more water from the heel
36
Pressure and Temperature Proifile- Well04
• Although claimed horizontal by drilling contractor, the static pressure/temp/resistivity shows downward deviation •Big ICD pore size (4/32 Inch in this case) create small drawdown and it is a challenge to have uniform drawdown along the well (15 psi vs 18 psi, 17% different)
37
Pressure and Temperature Profile- Well08
• Although claimed horizontal by drilling contractor, the static pressure/temp/resistivity shows downward deviation •Smaller ICD pore size (3/30 Inch in this case) create bigger drawdown and it is better for having uniform drawdown along the well (58 psi vs 55 psi, 5% different)
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Field A: Improving the hydrocarbon recovery • Horizontal wells with ICD completion • MSW approach for well modeling • 11% RF increase on “No ICD” case. • This happened through: Draw down management Gas suppression WBT
control
• ICD pore size can be further optimized! • Reservoir heterogeneity along the well
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Field A: Journey of recovery factor improvement Water injection Mobility control Idle well re-activation 42 Wells Phase 3 prospect Long HZ Well 6-8 m offset from OWC Project Phasing
32% 23% 20
>34%
Accurate TZ characterization Proper HZ and smart well modeling Economical phase 3 Optimizing the number of wells
16% 27 Wells Horizontal wells + ICD Gas cap gas reinjection 4 m offset from OWC
40
Field B: Optimized Production Strategy in a Malaysian Carbonate Oil Rim GAS Oil Recovery Recovery ( MMSTB) (BSCF)
Cases
Well No.
Original FDP
41
375.4
7+4
Opt. attempt (1)
38.3
383.1
7
•Known as gas field! •Concurrent Oil and Gas development •Oil and gas production through the same well •Dual smart completion with ICV •Development cost reduction
Optimized Well Design FDP well design
GAS CAP
OIL RIM Aquifer
41
Well Position vs EUR in Field B
•2 km HZ well •Gas offtake effect • Aquifer effect •ICD vs SSD
42
Field C: Withdrawal control from different zones
Z1
Z2
U9.1
Z1
U9.2
Z2
U8.0 2500
U7.0 50 45
•
10 m oil column
•
FCV with PDG application
•
Close performance monitoring
•
Valve optimization
•
PBU survey
2000
40
) d / 1500 b t s ( e t a R 1000 l i O
35
500
10
30 ) % ( 25 t u c 20 W 15
5 0
0
19-Sep-1019-Oct-10 18-Nov-10 18-Dec-1017-Jan-1116-Feb-11 18-Mar-11 17-Apr-11 17-May-11 Oil Rate (stb/d)
W/CUT
43
Improving the hydrocarbon recovery in Field C
Horizontal wells with ICD completion
Multi zone production with Flow Control Valve
HZ well and smart completion modeling
6% RF increase upon “No ICD” case.
Recommend longer HZ well, PDG, optimum well placement, pilot hole and contact monitoring
Recommend static/dynamic model revisit
44
Field D: Improving the hydrocarbon recovery
• Recovery factor vs GI/GP
Reactivate Idle Wells Side Tracks Infill Wells
46% • Journey of recovery factor improvement
34%
>50% Selective Water Injection Fencing at GOC Periphery at WOC
No Further Action 75% Idle Wells 45
RF Sensitivity to GI/GP in Field D
GI/GP Management Recovery factor vs GI/GP
46
Field E: Smart HZ Well Application in Small Oil Pocket
• 4 MMSTB STOIIP • 8 m oil column • Gas cap size M ratio=1.7 • Vertical well EUR=0.17 MMSTB • 500 m Smart HZ Well EUR=0.9 MMSTB • UDC= USD 18/bbl 47
Field G: New EOR Scheme EOR Scope: • • • • • •
50 MMscfd Gas Inj. 4 Downdip Injectors 50 kbwpd Water Inj. 5 Updip Injectors 22 Reactivations 4 Infill Producers
Gravity Assisted Simultaneous Water And Gas Injection
Recovery mechanisms • Re-pressurizing reservoir • Sweeping remaining oil towards new wells • Improved vertical sweep using gravity assistance • Pushing attic oil back down to producers • Reduced S with respect to gas in water swept
Field K: Do we need HZ well with ICD?
Oil column = 6 m
m = 2.0
Phi avg = 25 %, k avg = 500 md
Pini = 2100 psia, Tres = 226 deg F
Strong aquifer With Equalizer
RF,%
Standard Sandscreen
Standard Screen
15.46
Equalizer
18.75
49
Case 9: Smart Horizontal Well modeling in a Malaysian Oil Rim EP-F 3000
3.2E+06
3.01 2.79 2.60
2500
7% error over conventional methods 16% gain with ICD in well level 6% gain with ICD in field level
) Y A D / B T S ( e t a R d o r P l i O
2.4E+06 2000
1500
) B T S 1.6E+06 ( T P O
OPR OPT OPR-MC_GI_PERM_ICD3_1 OPT-MC_GI_PERM_ICD3_1 OPR-MC_GI_MSW_1 OPT-MC_GI_MSW_1
1000
800000 500
0 2010
2015
2020
2025
2030
0 2035
Date (YEARS)
FIELD 12500
2E+07
18.5 17.9 17.4
ICD+MSW No ICD 10000
ICD Design • Tubing OD 5.5”, ID 4.892” • ICD port size 3/32” • ICD interval 11m
) Y A D / B T S ( e t a R d o r P l i O
1.6E+07
MSW 7500 OPR OPT OPR-MC_GI_PERM_ICD3_1 OPT-MC_GI_PERM_ICD3_1 OPR-MC_GI_MSW_1 OPT-MC_GI_MSW_1
5000
2500
0 2010
1.2E+07 ) B T S ( T P 8E+06 O
4E+06
2015
2020
2025
2030
0 2035
50
Case 5: Withdrawal Mis-Management in Field F
Gas Cap production Oil loss to the gas cap
Lower RF
Z1
~ 2m TV GOC has receded Original Field GOC @ 1686.6 m TVDSS
Z2 Z3
Z4 Highest Known Water in NL_A3ST2 @ 1695.2 m TVDSS
Z5
Original Field OWC @ 1700.6 m TVDSS
Z6
51
Innovative Well Design and Off take Strategy East
WEST
C12 J18/19/2 0
C17 C20 B12 & B12ST1
C12ST1 K2025
52
Closing Remarks: •Oil rim: good business opportunity with sweet headaches! •Integration of innovative technical initiatives and new technologies •Real time/integrated reservoir management, monitoring and surveillances •Several gas fields and un-commercial assets turned in to attractive oil rim developments •Success cases on oil column thickness as low as 3 m and STOIIP as low as 3 MMSTB •Time to change our culture/mindset! Lets follow all the success factors
Oil rim development can be reality now! Lets move toward breaking the hydrocarbon recovery limit with lower cost! 53
Thank You! Question?
-1.5 m -Can we develop?!
54
Back Up Slides
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