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AB GEOS 2012_RS FINAL
- 1. Petroleum Development Oman 1 Geological Controls on Waterflood Performance, an example from a field in South Oman M.R.F. Shaikh, A.J.G. Faulkner, & Y. Al Busaidi PDO Paper Number: 1178244
- 2. Petroleum Development Oman 2 • Introduction • Field Summary – AB Field Stratigraphy – Geology overview • Facies and Pressure Trends in the AB Field – AB South and Far South Areas – AB Central and North Areas • Water Injection within the Gharif – History – AB Northern Area and AB Southern Area • Conclusions • Acknowledgements – Asset team and MOG and PDO Geological Controls on Waterflood Performance, an example from a field in South Oman
- 3. Petroleum Development Oman 3 AB Field Background and Development outline • The AB field is located in South Oman • Comprised of four isolated accumulations • Multiple stacked reservoirs: • Carboniferous-Permian Al Khlata • Permian Gharif • Mesozoic Kahmah Clastics. • Initial development has targeted the Fluvial Gharif Fmn • Gharif Formation consists of three members: • transitional marine/terrestrial basal member • two upper fluvial members. • The AB FDP initiated an inverted 5-spot WI in August 1998 in the Northern Area of the field where all three Gharif members were observed to be well developed. • The 5-spot WI trial resulted in a full field inverted 9-spot WI development over all four structures. • On completion of all of the Gharif wells it is clear that the subsurface development of the Gharif Reservoir is not as homogeneous as modeled in the FDP • It has been observed that reservoir connectivity within WI patterns is unable to sustain field production forecasts • By mapping regions of high and low quality reservoir facies it has been possible to plan for future infill well locations in order to ensure that the WI goals are met for the AB Field. 0 1000 2000 3000 4000 5000m 1:45000
- 4. Petroleum Development Oman 4 AB Field - Stratigraphy The main AB Field reservoirs are the basal sands of the Mesozoic Clastic (THMC-A1) and the significantly older Haushi Sicilicastic of the Gharif and Al Khlata Formations. The base of the Al Khlata is unconformable upon the Cambrian Ara. Age Group Formation Member Unit Sub-unit Depositional Environment THMC-A THMC-A1 Khuff Upper PTKFU Khuff Middle PTKFM Khuff Lower PTKFL HSGHU HSGHU-1 HSGHM-2 HSGHM-2 HSGHM-1B HSGHM-1A HSGHL-3 HSGHL-3.1 HSGHL-3.2 HSGHL-2 HSGHL-2.1 HSGHL-1 HSGHL-1.1 Rahab HSAK1R Glacio-Lacustrine HSAK-1 HSAK-5U HSAK-5L HSAK-9U HSAK-9M HSAK-9L Cambrian Ara QA HSAK P5 HSAK P9 Al Khlata Glacio-lacustrine/fluvial Al Khlata Permo- Carboniferous Haushi Arid/ephemeral fluvial Arid/ephemeral Deltaic Fluvial-Deltaic Shallow Marine Translittoral - Floodplane - lacustrine HSAK P1 HSGHM-1 Middle Gharif HSGHL-3 HSGHL-2 HSGHL-1 Lower Gharif PTKFKhuffAkhdar Permo- Triassic HSGHUUpper Gharif GharifPermian Undifferentiated Mesozoic Clastics KahmahMesozoic THMC Fluvial - Deltaic- Paralic Tithonian & Base Jurassic Unconformities Hercynian, Early Devonian & Angudan Unconformities
- 5. Petroleum Development Oman 5 Gharif Variations ABJ-30H1 ABJ-36H1 ABJ-76H1ABJ-10H1 ABJ-68H1ABJ-71H1ABJ-9H1ABJ-33H2ABJ-31H2ABJ-22H1 ABJ-26H1ABJ-66H1 ABJ-49H1 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 Distance, [m] -2000-1600-1200 -800 -2000-1600-1200 -800 Z,[m] 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 Distance, [m] -2000-1600-1200 -800 -2000-1600-1200 -800 Z,[m] 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 -2200 -2000 -1800 -1600 -1400 -1200 -1000 -800 -600 -2200 -2000 -1800 -1600 -1400 -1200 -1000 -800 -600 MCA Khuff PTKFR PTKFC PTKFL Gharif HSGHU HSGHM-2 HSGHL-3 HSGHL-2 HSGHL-1 Al Khlata HSAKR HSAK-1 HSAK-5 HSAK-9 Zones 0 1000 2000 3000 4000 5000m 1:45000 A B 0 1000 2000 3000 4000 5000m 1:45000 AB-SOUTH Area • UGh & MGh poor sand development. • LGh very well developed in the East of the Southern Area with good lateral continuity • Strong LGh pressure communication in East of the Southern Area. • LGh poorly developed in the West of the Southern Area, though are pressure depleted AB-CENTRAL Area • UGh & MGh poor sand development • LGh well developed in Northern section of the Central Area, but worsens to the South. • Lateral Continuity better in the North than the South This is also reflected in the pressure data. AB-NORTH Area • UGh & MGh good sand development • LGh poor sand development • Lateral continuity is evident in all Gharif units. • Pressure communication in the MGh and LGh across the Northern Area A B
- 6. Petroleum Development Oman 6 G & G issues Low NG sandHigh NG sand Main Stacked Channel Fairway Lower Gharif Channel Sands present but isolated Axial Flow direction Kh is expected to be higher parallel to the axial flow direction Kh1 > Kh2 Kh1 Kh2 5 km
- 7. Petroleum Development Oman 7 G & G issues Low NG sandHigh NG sand Lower Gharif Primary Target Upper & Middle Gharif Secondary Target Faulting Faulting across the field is seen to juxtapose the Primary Target Lower Gharif Reservoir against the Secondary Target Middle and Upper Gharif Sands which Do not appear to have as much lateral and vertical connectivity as observed in the Lower Gharif. Were sand is present either side of the faults there is communication and fluid moves across faults The vertical separation of faulted zones observed in wells is up to 20 m. 5 km
- 8. Petroleum Development Oman 8 0 1000 2000 3000 4000 5000m 1:45000 Poor developed UGh & MGh with no lateral continuity Moderate developed LGh with poor lateral continuity Poor developed UGh & MGh with poor lateral continuity Very well developed LGh with Exceptional lateral continuity Poor developed UGh & MGh with no lateral continuity Moderate developed LGh with reasonable lateral continuity Poor developed UGh & MGh with no lateral continuity Moderate developed LGh with poor lateral continuity Poor developed UGh & MGh with no lateral continuity Moderate developed LGh with reasonable lateral continuity Moderate developed UGh & MGh with poor lateral continuity Well developed LGh with good lateral continuity Well developed UGh & MGh with good lateral continuity Moderate developed LGh with reasonable lateral continuity 0 1000 2000 3000 4000 5000m 1:45000 AB North – Northern Flank Area • MGh and LGh-3 has limited to no pressure communication with AB North - Central Area • LG-1 & 2 are not completed in the AB North Flank Area • Well data shows that the LGh-1 is pressure depleted Fault acting as baffle across MGh Fault acting as potential baffle across LGh AB North – Central Area • MGh – In communication with nearby wells and AB North - Northern Flank Area; but no communication with AB North – Southern Flank Area • LGh – LGh-1 is in limited communication with nearby wells – LGh 2&3 are in communication with AB North Southern Flank Area – LGh 2&3 has limited communication with AB North – Northern Flank Area AB North – Southern Flank Area • MGh - limited pressure communication with AB North – Central Area • LGh - LGh-1 limited pressure communication with AB North – Central Area • LGh – LGh 2&3 Well data shows pressure communication with AB North – Central Area AB Central – Northern Flank Area • LGh – Wells are in communication in all LGh sub-zones • LGh - LGh-2 is the main reservoir, then LGh1 AB South – Western Flank Area • This area has no/very limited communication with the rest of the South Fault acting as baffle across LGh Fault acting as baffle across MGh and LGh AB Central– Eastern Flank Area • Has substandard reservoir properties • Acts as a barrier between northern and southern areas in the Central Area AB Central– Southern Flank Area • LGh-1 & 3 are more productive than the LGH-2 AB South– Eastern Flank Area • Wells are in communication • Some wells show waterflood response • This area has lower pressure than South Western area Fault acting as baffle across LGh AB Far South– Northern Flank Area • Higher pressure (+4000KPa) than and not in communication with the AB Far South Southern Flank area AB Far South– Southern Flank Area • Wells are in communication with each other, but not in communication with the AB Far South Northern Flank area North AB Area Well developed UGh & MGh reservoir Central AB Area Moderate developed UGh and MGh reservoir Well developed LGh reservoir South AB Area Poor developed UGh and MGh reservoir on flanks Excellent developed LGh reservoir in center Far South AB Area Poor UGh, MGh & LGh reservoirs Facies and Pressure Trends
- 9. Petroleum Development Oman 9 RFT Pressure vs. Time (at Datum) Combined Gharif Reservoirs prior to Injection MDT Pressure Distribution of Gharif Reservoir •The initial Reservoir Pressure Gharif 15450 kpa at datum -1240 m. •The current Gharif Reservoir pressure in the range 4000-12000 kpa.
- 10. Petroleum Development Oman 10 UGh & MGh have better sand development than the LGh but lateral continuity between wells is evident in all three units. There is evidence of pressure communication in the MGh and LGh across the Northern Area -1350 -1350 -13 50 -1350 -13 50 -1 35 0 -12 90 -132 0 -1 26 0 -1440 -13 80 -138 0 -12 60 -1320 -1 32 0 -1320 -1320 -1290 -129 0 -12 90 -1 29 0 -1200 -1260 -1 26 0 -1500 -1230 -12 30 -144 0 -1 38 0 -138 0 -1380 -1 41 0 -1410 -1410 -1470 1410 -144 0 -12 90 -1 29 0 -1 26 0 -1320 -1320 -1 41 0 -1440 0 250 500 750 1000 1250m 1:10000 HSGHU HSGHM-2 HSGHL-3 HSGHL-3 HSGHL-2 HSGHL-1 HSAKR 20.00 150.00GR 0.10 50.00LLD 0.10 50.00LLS 0.45 -0.15CNL 1.95 2.95RHOB 0.3500 -0.3500P OR_Cutoff -1.0000 1.0000S o_Cutoff 5000 20000RFT OpenOpen Open Open Open PERFS HSGHL-3 ABJ-14H1 [MD] 20.00 150.00GR 0.10 50.00LLD 0.10 50.00LLS 0.45 -0.15CNL 1.95 2.95RHOB -1.0000 1.0000S o_Cutoff 0.3500 -0.3500P OR_Cutoff 5000 20000RFT OpenOpen Open Open OpenOpen PERFS HSGHL-3 ABJ-10H1 [MD] 20.00 150.00GR 1.00 50.00LLD 0.45 -0.15CNL 1.95 2.95RHOB -1.0000 1.0000S o_Cutoff 0.3500 -0.3500P OR_Cutoff 5000 20000RFT ClosedClosedClosedClosedOpenOpenOpen PERFS HSGHL-3 ABJ-30H1 [MD] 20.00 150.00GR 0.10 50.00LLD 0.10 50.00LLS 0.45 -0.15CNL 1.95 2.95RHOB -1.0000 1.0000S o_Cutoff 0.3500 -0.3500P OR_Cutoff 5000 20000RFT Open Open Open Open OpenOpenOpen PERFS HSGHL-3 ABJ-22H1 [MD] 20.00 150.00GR 0.10 50.00LLD 0.10 50.00LLS 0.45 -0.15CNL 1.95 2.95RHOB -1.0000 1.0000S o_Cutoff 0.3000 -0.3000P OR_Cutoff 5000 20000RFT OpenOpenOpen PERFS HSGHL-3 ABJ-40H3 [MD] 20.00 150.00GR 0.10 50.00LLD 0.10 50.00LLS 0.45 -0.15CNL 1.95 2.95RHOB -1.0000 1.0000S o_Cutoff 0.3000 -0.3000P OR_Cutoff 5000 20000RFT Open OpenOpenOpenOpen PERFS HSGHL-3 ABJ-44H2 [MD] HSGHU HSGHM-2 HSGHL-3 HSGHL-3 HSGHL-2 HSGHL-1 HSAKR Section flattened on Base Gharif A B AB Field Northern Area - Geology A B UGhLGh MGh
- 11. Petroleum Development Oman 11 -1350 -1350 -13 50 -1350 -13 50 -1 35 0 -12 90 -132 0 -1 26 0 -1440 -13 80 -138 0 -12 60 -1320 -1 32 0 -1320 -1320 -1290 -129 0 -12 90 -1 29 0 -1200 -1260 -1 26 0 -1500 -1230 -12 30 -144 0 -1 38 0 -138 0 -1380 -1 41 0 -1410 -1410 -1470 1410 -144 0 -12 90 -1 29 0 -1 26 0 -1320 -1320 -1 41 0 -1440 0 250 500 750 1000 1250m 1:10000 AB Field Northern Area - Structure ABJ-14H1 ABJ-10H1 ABJ-30H1 ABJ-22H1 ABJ-40H3 ABJ-44H2 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 -1450 -1400 -1350 -1300 -1250 -1200 -1450 -1400 -1350 -1300 -1250 -1200 Symbol legend HSGHU HSGHM-2 HSGHL-3 HSGHL-2 HSGHL-1 HSAKR HSAK-1 HSAK-5 HSAK-9 ABJ-14H1 ABJ-10H1 ABJ-30H1 ABJ-22H1 ABJ-40H3 ABJ-44H2 0 200 400 600 800 1000m 1:10000 A B ABJ-14H1 ABJ-10H1 ABJ-30H1 ABJ-22H1 ABJ-40H3 ABJ-44H2 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 -1450 -1400 -1350 -1300 -1250 -1200 -1450 -1400 -1350 -1300 -1250 -1200 Symbol legend HSGHU HSGHM-2 HSGHL-3 HSGHL-2 HSGHL-1 HSAKR HSAK-1 HSAK-5 HSAK-9 ABJ-14H1 ABJ-10H1 ABJ-30H1 ABJ-22H1 ABJ-40H3 ABJ-44H2 0 200 400 600 800 1000m 1:10000 Faults and Folding has resulted in localised compartmentalisation of the Northern Area of the AB Field. There is evidence of pressure communication in the MGh and LGh across the Northern Area A B
- 12. Petroleum Development Oman 12 AB Field Northern Area - Pressure -1350 -1 350 -1350 -1350 -1 350 -138 0 -138 0 -1380 -1 380 -1 410 -1260 -1320 -1 320 -1320 -1290 -1290 -1290 -1200 -1260 -1260 -1500 -1230 -1230 -1440 -1 380 -1380 -1 410 -1410 -1470 -1410 -1440 -129 0 -1 290 -1 260 -1320 -1320 -1 410 -1440 0 250 500 750 1000 1250m 1:15000 AB North – Northern Flank Area • MGh and LGh-3 has limited to no pressure communication with AB North - Central Area • LG-1 & 2 are not completed in the AB North Flank Area • Well data shows that the LGh-1 is pressure depleted AB North – Central Area • MGh – In communication with nearby wells and AB North - Northern Flank Area; but no communication with AB North – Southern Flank Area • LGh – LGh-1 is in limited communication with nearby wells – LGh 2&3 are in communication with AB North Southern Flank Area – LGh 2&3 has limited communication with AB North – Northern Flank Area AB North – Southern Flank Area • MGh - limited pressure communication with AB North – Central Area • LGh - LGh-1 limited pressure communication with AB North – Central Area • LGh – LGh 2&3 Well data shows pressure communication with AB North – Central Area Fault acting as baffle across MGh 0 2000 4000 6000 8000 10000 12000 14000 16000 18000 Aug-87 May-90 Jan-93 Oct-95 Jul-98 Apr-01 Jan-04 Oct-06 Jul-09 Pressure,kPa TIME AB - North Area Sub Zone LowerGH Initial Reservoir Pressure @ -1240 TVD ss =~16000 kPa Initial Reservoir Pressure Fault acting as potential baffle across LGh
- 13. Petroleum Development Oman 13 LG3 LG2 LG1 LG3 LG2 LG1 AB-NA WF Pattern Northern Flank AB-NB WF Pattern North Area West Flank AB-NC WF Pattern North Central Area AB-ND WF Pattern North Area East Flank GH Prod 11 WI 5 WSW 2 CIW 2 AK 1 GH-UGH-U GH-MGH-M AB-NE WF Pattern North Area Southern Flank AB Field Northern Area - Wells A B C D E
- 14. Petroleum Development Oman 14 AB North Area has 5 injectors: • Main focus has been to increase reservoir pressure and increase the net voidage in this area of the field • General observation: • Very limited injectivity into LG-1 in AB North Area: only 2 out of five injectors (C & D) • Structure and Facies are seen to play a major role in subsurface flow in AB North • LGh is not as well developed compared to UGh & MGh in AB North Area • Local faults are seen to inhibit subsurface flow in specific zones • AB-NA WI is seen to support offset wells to the West & South in the MGh and LGh • AB-NB WI is seen to support in the LGh only due to poor connectivity in the shallower zones • AB-NC WI is seen to support all offset wells in the UGh & MGh • AB-ND WI is supporting wells to the south-west and north-east – possible fault interference • AB-NE WI supports wells to the north in the MGh. AB North Area – Pattern Summary A B C D E
- 15. Petroleum Development Oman 15 0. 5. 10. 15. 20. 25. 30. 1 10 100 1000 Aug-87 Aug-88 Aug-89 Aug-90 Aug-91 Aug-92 Aug-93 Aug-94 Aug-95 Aug-96 Aug-97 Aug-98 Aug-99 Aug-00 Aug-01 Aug-02 Aug-03 Aug-04 Aug-05 Aug-06 Aug-07 Aug-08 Aug-09 Aug-10 OilWellCount OilRatem3/d Date NorthArea Production Performance OilCD North Depl AB Field Production History – Northern Area Start of AB North Area Waterflood Aug 1998 High Low Oil Gain
- 16. Petroleum Development Oman 16 AB Southern Area – Geology PTKFC PTKFL HSGHU HSGHM-2 HSGHL-3 HSGHL-3 HSGHL-2 HSGHL-1 HSAKR -14.01 375.82GR -14.01 375.82ECGR 0.10 50.00RES_DEP 0.10 50.00RES_MED -0.02 0.88NPHI 1.95 2.95RHOB -1.0000 1.0000SHNET 0.3000 -0.3000PORNET 5000 20000RFT HSGHL-3 ABJ-75H1 [MD] 20.00 150.00GR 0.10 50.00RES_DEP 0.10 50.00RES_MED 1.95 2.95RHOB -1.0000 1.0000SHNET 0.3000 -0.3000PORNET 5000 20000RFT HSGHL-3 ABJ-45H2 [MD] 20.00 150.00GR 2.00 50.00RES_MED 2.00 50.00RES_DEP 0.45 -0.15CNL 1.95 2.95RHOB -1.0000 1.0000SHNET 0.3000 -0.3000PORNET 5000 20000RFT HSGHL-3 ABJ-59H1 [MD] 20.00 150.00GR 0.10 50.00LLD 0.10 50.00LLS 0.45 -0.15CNL 1.95 2.95RHOB -1.0000 1.0000SHNET 0.5000 -0.5000P ORNE T 5000 20000RFT ClosedClosedClosedClosedClosedClosed PERFS HSGHL-3 ABJ-2H1 [MD] 7.97 195.71GR 7.97 195.71ECGR 0.10 50.00RES_DEP -0.05 0.71NPHI 1.95 2.95RHOB -1.0000 1.0000SHNET 0.3000 -0.3000PORNET HSGHL-3 ABJ-71H1 [MD] 10.39 226.32GR 10.39 226.32ECGR 0.10 50.00RES_DEP 0.10 50.00RES_MED 1.95 2.95RHOB -1.0000 1.0000SHNET 0.3000 -0.3000PORNET 5000 20000RFT HSGHL-3 ABJ-50H1 [MD] 20.00 150.00GR 0.10 50.00LLD 0.10 50.00LLS 0.45 -0.15CNL 1.95 2.95RHOB -1.0000 1.0000S o_Cutoff 0.3500 -0.3500P OR_Cutoff 5000 20000RFT OpenOpenOpenOpenOpen PERFS HSGHL-3 ABJ-23H1 [MD] HSGHU HSGHM-2 HSGHL-3 HSGHL-3 HSGHL-2 HSGHL-1 HSAKR -1 35 0 -135 0 -1350 -1350 -1350 -1 35 0 -1 380 -1290 -141 0 -1320 -1 32 0 -12 60 -1290 -1 260 -1440 -138 0 -1 410 -1260 -1 32 0 -132 0 -1320 -129 0 -1 29 0 -12 90 -1200 -126 0 -15 00 -12 30 -138 0 -1380 -1380 -1410 -1410 -1470 0 500 1000 1500 2000 2500m 1:15000 The LGh has excellent sand development to the across the whole Southern AB Area – specifically in the east. There is evidence of pressure communication in the LGh across the Southern Area X Y X Y UGhLGh
- 17. Petroleum Development Oman 17 AB Southern Area – Structure X Y ABJ-75H1 ABJ-42H2 ABJ-50H1 ABJ-23H1 400 800 1200 1600 2000 2400 2800 3200 400 800 1200 1600 2000 2400 2800 3200 Distance, [m] -1800-1600-1400-1200-1000 -1800-1600-1400-1200-1000 Z,[m] 400 800 1200 1600 2000 2400 2800 3200 400 800 1200 1600 2000 2400 2800 3200 Distance, [m] -1800-1600-1400-1200-1000 -1800-1600-1400-1200-1000 Z,[m] 400 800 1200 1600 2000 2400 2800 3200 400 800 1200 1600 2000 2400 2800 3200 -1900 -1800 -1700 -1600 -1500 -1400 -1300 -1200 -1100 -1000 -1900 -1800 -1700 -1600 -1500 -1400 -1300 -1200 -1100 -1000 MCA Khuff PTKFR PTKFC PTKFL Gharif HSGHU HSGHM-2 HSGHL-3 HSGHL-2 HSGHL-1 Al Khlata HSAKR HSAK-1 HSAK-5 HSAK-9 Zones 0 250 500 750 1000 1250m 1:14000 0 1000 2000 3000 4000 5000m 1:45000 X Y
- 18. Petroleum Development Oman 18 AB South Area – Pattern Performance 0 2000 4000 6000 8000 10000 12000 14000 16000 18000 Jan-04 May-05 Oct-06 Feb-08 Jul-09 Nov-10 Apr-12 Pressure,kPa Time AB Field - Southern Area RFT Pressure vs. Time Lower Gharif Zone Easten flank AB South Area Press @ -1240 TVD ss =14500 kPa 2011 new wellsWestern side wells Eastern side wells Initial Reservoir Pressure @ -1240m TVD ss =~16000 kPa West side of South Area Press @ -1240 TVD ss =8500-9000 kPa East side of South Area Press@ -1240 TVD ss =7500 kPa (4000 with no INJ) 2010 new wells -1350 -1350 -1350 -1 350 -1380 -1380 -1290 -1410 -1320 -1 320 -1260 -1290 -1260 -1440 -1380 -1380 -1410 -1260 -1 320 -1320 -1320 -1320 -1290 -1 290 -1290 -1200 -1260 -1500 -1230 -1230 -1440 -1380 -1380 -1380 -1410 -1410 -1470 0 500 1000 1500 2000 2500m 1:15000 AB Central– Southern Flank Area • LGh-1 & 3 are more productive than the LGH-2 AB South– Eastern Flank Area • Wells are in communication • Some wells show waterflood response • This area has lower pressure than South Western area Fault acting as baffle across MGh and LGh Fault acting as baffle across LGh AB South – Western Flank Area • This area has no/very limited communication with the rest of the South
- 19. Petroleum Development Oman 19 AB Southern Area Wells Three AB SA WF Patterns AB-SA WF Pattern in the South East Central AB-SB WF Pattern in the Southern South Flank AB-SC WF Pattern in the South West Central GH Prod 11 WI 4 CIW 2 AK/MZ 2 LG3 LG2 LG1 LG3 LG2 LG1 N 42 B A C
- 20. Petroleum Development Oman 20 AB Southern Area Pattern Performance 0 10 20 30 40 50 60 70 80 90 100 1.00 10.00 100.00 1000.00 Jan-08 May-08 Sep-08 Jan-09 May-09 Sep-09 Jan-10 May-10 Sep-10 Jan-11 May-11 Sep-11 Watercut% Oil/Liquidratem3/d South Area Production Performance OilCD LiquidCD oildepletion WaterCut AB-SB WF AB-SA-WF AB-SC-WF 6 OP wells High Low Oil gain in South AB Field
- 21. Petroleum Development Oman 21 AB South Area Pattern Summary: Three WI currently impacting flow in the AB South area. Well data show that 3 wells have responded to WF out of 9 producers currently producing from GH. Well data show that the East of the AB South area is responding better to the West – better rock quality to the East A Tracer Injection in AB-A & AB-C has been recommended to identify pattern connectivity, flow path, confirm WF response An additional 3 -4 new wells locations have been recommended of which two have been drilled AB South Area – Pattern Summary N 42 B A C
- 22. Petroleum Development Oman 22 AB Field Production History - Southern Area 0 10 20 30 40 50 60 70 80 90 100 1 10 100 1000 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Jan-08 Jan-09 Jan-10 Jan-11 BS&W,% Rate(m3/d) Date AB - GH South Production History Start WI OilCD LiquidCD OilWellcount WaterCut AB -SB AB-SA AB-SC High Low
- 23. Petroleum Development Oman 23 • The Gharif reservoir in each accumulation within the AB Field responds to Water injection in a unique way due to a combination of Facies variations and Structural controls. • Vigilant monitoring of production and pressure data has allowed an improved understanding of to subsurface fluid dynamics to be modeled • Facies Controls on WF include reservoir quality, connectivity and lateral continuity across the field • Structural Control on WF include compartmentalization due to minor salt related faulting and folding. • The resultant pressure distribution illustrates both production and injection history within the target reservoir and illustrates the location of superior connected pay within the field • The results of this work has allowed for improved production forecasts to be made as well as allowed for a more simplified strategic well placement decision making process Conclusions
- 24. Petroleum Development Oman 24 The Authors wish to Thank Field Team members MOG & PDO Acknowledgements