Integrated Study Leading to Discovery of Thin Pay Sands and Challenges Associated with Development. Shaikh Abdul Azim

Transcription

1 Integrated Study Leading to Discovery of Thin Pay Sands and Challenges Associated with Development Shaikh Abdul Azim February 10, 2014

2 Outline Location and Geological Setting Zubair in RA and SA Fields New Oil Find and surge of activity Integrated Study for developing thin pays Trapping in SA compared to RA Development Strategy Challenges Achievements Opportunities

3 Raudhatain and Sabiriyah Fields Raudhatain Iraq Kuwait Ratqa Southeast Ratqa Abdali Bahrah Medina FAILAKA ISLAND Arabian Gulf Sabiriyah Dharif Khashman Abduliyah Minagish KUBER ISLAND Greater Burgan QAROH ISLAND Saudi Arabia Umm Gudair UMM AL-MARADEM ISLAND AL-KHIRAN Wafra 3 N

4 Zubair Reservoir in North Kuwait GR + Raudhatain SHALE UPPER 1,400 Feet SAND SHALE Sabiriyah SAND MIDDLE SHALE SAND

5 Upper Zubair Sand Fluid Distribution in RA and SA

6 Middle Zubair Sand Fluid Distribution in RA and SA

7 Zubair in RA and SA Fields Raudhatain Field A major reservoir: Commercial production for 5 decades Second highest contributor to production Highest dry oil producer Sabiriyah Field Not considered to have commercial oil till 2006

8 South Sabiriyah: Hydrocarbon in Zubair/Ratawi Lower Zubair Sand: Condensate

9 Fluid Contacts Integrated Study Sequence Stratigraphy Depositional Environment Fault Seal, Pressure difference Structural History; Regional correlations Seismic Signatures for Channel Definition Sediment transport direction Oil migration Oil occurrence in Sabiriyah Zubair and Ratawi

10 Zubair Reservoir Reservoir Architecture and Trapping in Raudhatain 11

11 Sequence Stratigraphy

12 Depositional Model

13 Depositional Model

14 Raudhatain Correlation of Zubair in RA and SA wells Sabiriyah INTER FIELD Correlation

15 Correlation of Zubair/Ratawi in RA and SA wells

16 W E KL MU RA BH BU Regional correlation within the Zubair Formation along depositional dip.

17 Raudhatain Field: Reservoir Pressure declining with time

18 Pressure

19 Trapping Water Zone and Leaked oil Zone in Middle Zubair Tar in Upper Zubair Sand Tar All thick channels in UZ and MZ leaked Highly faulted SA structure High NTG: less clay smearing across fault plane Conductive fault planes

20 How Oil is trapped in SA-Zubair? 1. Thin Sands within Shales

21 How Oil is trapped in SA-Zubair? 2. Thick sand bodies in LZSD: Thicker Shales above

22 Role of Fault: Not unique OWC in UZSD

23 Not unique OWC in UZSD/UZSH UZSD UZSH

24 Compartment Compartment Depth Saturation Plots for Fluid Contacts High Sw at shallower depth show leaked compartments

25 Oil: Source to Trap

26 Oil Entrapment in Zubair

27 Development Strategy South Sabiriyah: Better quality oil bearing sands Targeting Channel Sand above Ratawi Shale Developing thin sands Moving towards north Ratawi Shale

28 Channel in Z_ls erodes Ratawi shale Difficult to predict: SA-290 lying less than 500 m misses the channel

29 Mapping Channel from Seismic attribute as a Guide Thickest Oil bearing Layer in Sabiriyah Zubair

30 Sand thins towards North Source from South Observed in 4 Wells Channel trend Established from RA field with more well Control Minimum Channel width 400m Net Sand thickness of Z_ls Channel in Z_ls

31 Thin Pays South North

32 Thin Pays South North

33 Net Pay of Bottom Sand (Z_ls6) PHI>=8% PHI>=12%

34 Prospective Areas Green: Oil Downto Blue: Transition

35 Developing Ratawi Shale: A stratigraphic trap Average Thickness: 8 ft Cemented Sandstones

36 Light oil in a thin shoreface sand Gross thickness decreases towards North Sand pinch out towards North Source from South Gross thickness of RS66 Net Sand thickness

37 Phases of Development

38 Phase-2 MRC (Horizontal Wells) for 4-8 ft sands with poorer reservoir quality Phase-1

39 Z_ls6 Planned to develop with Horizontal Wells PHI>=8% PHI>=12%

40 Z_ls " Shoe First deep Horizontal well

41 SA-A Oil Rate: 2706 BOPD W/C: 0% Choke size: 64/64 WHP: 1092 psi

42 Liquid Rate Oil Rate WC GOR Choke WHP BLPD 3074 BOPD 24% / psi BLPD 2948 BOPD 15% / psi Days 103 Horizontal Length 2130

43 The targeted thin sand in the pilot hole Initial Testing Results Choke Qoil GOR WHP WC 32/ / Days 123 Horizontal Length 1709

44 Liquid Rate: 2140 BLPD Oil Rate: 1753 BOPD W/C: 18% Choke size: 32/64 WHP: 951 psi Horizontal Length 1097 Shale Intv(bottom) 60 Coal Interval 140 Sand Interval 897 Days: 115

45 Deep MRC Wells Long Rig time Challenges Thick section: Shale dominated towards bottom Shale at top of Target Geo-steering, within 4-7 ft sand, tool reliability Short landing casing Casing buckling while lowering Presence of coal at top of Target Reservoir Pressure

46 Short landing casing PIL Hor Z_ls " Shoe 11721

47 Days 123 Casing buckling while lowering The targeted thin sand in the pilot hole

48 Presence of coal at top of Target Geo-steering, within 4-7 ft sand, tool reliability Horizontal Length 1097 Shale Intv(bottom) 60 Coal Interval 140 Sand Interval 897 Days: 115

49 Faulted Structure

50 Achievements Oil production 20 million barrels Very high quality Dry oil Supporting NK Production Target Experience of developing similar sands in other Reservoirs

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53 Opportunities Thicker Channels of Z_ls towards south and other parts of field Commercial production from South Sabiriyah extend to North Deeper OWC towards South: to spill point Porous areas for Ratawi Shale Fault compartments in UZSH,UZSD,MZSD with independent oil pools adding to STOIIP

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