Locating the Remaining Oil in a Complex Field: The Pierce Field Redevelopment

Transcription

1 Locating the Remaining Oil in a Complex Field: The Pierce Field Redevelopment Presenter: Michael Porter Team: David Bateman, Thaddeus Ehighebolo, Fiona Haldane, Ash Holland, Jackie Kechichian & Ewan Robertson Partners: Use this area for cover image (height 6.cm, width cm)

2 Contents Background Production Complexity Methodology Results Portfolio Future Operations Summary

3 Pierce Background 6 E & A Wells 7 Oil Producers Gas Injectors 4 Water Injectors Field History and Development 9.% Shell share Reservoir: Paleocene-Eocene Forties turbidite South Pierce discovered by Ranger in 97 North Pierce discovered by BP in 990 Production began in 999 under Enterprise

4 Pierce Production n Current Field STOIIP is ~00 MM bbl n Cumulative oil production will be ~0 MM bbl with current development n Expectation recovery factor is %, current recovery factor is 4% which leaves 70 MM bbls to still be recovered Pierce Oil & Water Profile Wells: A ll Blocks: A ll & Subcycles: A ll Oil Ra te Wa te r Ra te BSW (fra c) Cum Oil Cum Wa t Cum Gross , , , ,000 BSW (frac) Rates (p lbl/cd ) Cum (bl*e) 0, ,000 um (scf*e6) Pierce Gas Profile Wells: A ll Blocks: A ll & Subcycles: A ll Ga s Ra te Cum Ga s GOR GLR Jan-0 Jan-09 Jan-0 Jan-07 Jan-06 Jan-0 Jan-04 Jan-0 Jan-0 Jan-0 Jan-00 Jan-99 Jan-9 Jan-97 0 Jan ,000,000 00,000 0,000 0,000 4

5 Production Constraint Pierce Oil & Water Profile Wells: A ll Blocks: A ll & Subcycles: A ll Facility Gas Constraint Wa te r Ra te BSW (fra c) Cum Oil Cum Wa t Cum Gross , FPSO can only process 0 MMSCFs/ day ,000 All future wells must have a lower GOR, otherwise they steal production from existing producers , Cum Ga s GOR Jan-0 Jan-09 Jan-0 Jan GLR 0,000,000 00,000 0,000 0,000,000 00,000 6,000 0,000 4,000 00,000,000 Jan-0 Jan-09 Jan-0 Jan-07 Jan-06 Jan-0 Jan-04 Jan-0 Jan-0 Jan-0 Jan-00 Jan-99 0 Jan-9 0,000 Jan-97 Rates (scf/cd *E) Cum (scf*e6) Ga s Ra te Jan-06 Current strategy is to place wells as Pierce Gas Profile Wells: A ll Blocks: A ll & Subcycles: A ll close to OWC as possible n Jan-0 Jan Jan-0 Jan-0 Jan-0 Jan-00 Jan-99 Jan-9 Jan-97 0,000 0 BSW (frac) ,000 Jan-96 n All produced gas is re-injected Jan-96 n Rates (p lbl/cd ) Cum (bl*e) n.00 GOR & GLR Oil Ra te 0,000 0

6 Pierce Complexity # Salt Diapirs and Structure n Difficult seismic imaging creates a large amount of uncertainty (salt diapir/reservoir boundary, reservoir thickness and time-depth calculations) n Between +/ ft depth uncertainty depending on well control n Drilling obstacle Salt overhang shadows reservoir Salt/Reservoir boundary poorly imaged Steeply dipping reservoir: >70o Forties Sandstone: thins up-dip 6

7 Pierce Complexity # Sedimentology Distal Forties Turbidite with two main periods of deposition Lower Forties Sand deposition constrained by infilling topography created by salt diapirism Upper Forties Sand deposited in a more sheet-like fashion with increased shale drape preservation Lower Forties conceptual depositional system 7

8 Pierce Complexity # Oil-water Contact Different theories throughout the field s history Few OWC drilled and vary between ~490 ~040 ft tvdss Pressure and fluid changes observed while drilling across faults N S N S Gas Oil Water Tilted OWC contact schematic Stepped OWC contact schematic

9 Methodology Part- Data gathering & QC Full Integration: collect and use ALL data Fault Model x z z KEY E&A Well Oil Producer Water Injector Gas Injector Fault Ax A4 A9 A7z A7 A A Az A0 4 Ay B4a B 0 B B N 6 9

10 Methodology Part- Data gathering & QC Full Integration: collect and use ALL data Fault Model Oil-Water Contacts x z z KEY E&A Well Oil Producer Water Injector Gas Injector Fault Ax A4 A9 A7z A7 A A Az A0 4 Ay B4a B 0 B B N 6 0

11 Methodology Part- Data gathering & QC Full Integration: collect and use ALL data Fault Model Oil-Water Contacts WUTs & ODTs x z Ax A4 z KEY E&A Well Oil Producer Water Injector Gas Injector Fault A9 A7z A Az A7 A A0 4 Ay B4a B 0 B B N 6

12 Methodology Part- Data gathering & QC Full Integration: collect and use ALL data Fault Model Oil-Water Contacts WUTs & ODTs Formation pressure and RFT data x z Ax A4 A9 A 7 z KEY E&A Well Oil Producer Water Injector Gas Injector Fault A7z A Az A A0 4 Ay B4a B 0 B B N 6

13 Methodology Part- Data gathering & QC Full Integration: collect and use ALL data Fault Model Oil-Water Contacts WUTs & ODTs Formation pressure and RFT data Chemical tracer studies x z Ax A4 A9 z KEY E&A Well Oil Producer Water Injector Gas Injector Fault A7z A Az A7 A A0 4 Ay B4a B 0 B B N 6

14 Methodology Part- Data gathering & QC Full Integration: collect and use ALL data Fault Model Oil-Water Contacts WUTs & ODTs Formation pressure and RFT data Chemical tracer studies Geochemistry x z Ax Increased Mixing A4 z KEY E&A Well Oil Producer Water Injector Gas Injector Fault A9 A7z A Az A7 A A0 4 Ay B4a B 0 B B 6 4

15 Methodology Part- Data gathering & QC Full Integration: collect and use ALL data Fault Model Oil-Water Contacts WUTs & ODTs Formation pressure and RFT data Chemical tracer studies Geochemistry 4D x z Ax A4 A9 A7 z A7z KEY E&A Well Oil Producer Water Injector Gas Injector Fault A A Az A0 4 Ay B4a B 0 B B N 6

16 Methodology Part- Data gathering & QC Full Integration: collect and use ALL data Fault Model Oil-Water Contacts WUTs & ODTs Formation pressure and RFT data Chemical tracer studies Geochemistry 4D Production data x Dry oil, no water production N z Ax A4 z KEY Gas coning from injector E&A Well Oil Producer Water Injector Gas Injector Fault A9 A7z A Az A7 A A0 4 Ay B4a B 0 B B Producer watered out 6

17 Methodology Part- Interpretation & STOIIPs Base Case Original OWC & GOC Field GRV calculated using interpreted: Fluid Contacts Salt Diapir extent Time-depth conversion Upscaling of petrophysical data to give reservoir property models A range of static in-place volumes calculated using Monte Carlo simulations and Petrel x z GOC Ax A4 z KEY OWC E&A Well Oil Producer Water Injector Gas Injector Fault A9 A7z A Az A7 A A0 4 Ay B4a GOC B 0 B 6 B 7

18 Methodology Part- Calculate remaining volumes per sector Field divided up into sectors and assumed to have uniform contacts x Produced volume of oil, water and gas assigned to each sector using historical data and PLTs Remaining volume per sector calculated both statically and dynamically Static volumes calculated using scenario based approach by back calculating volumes into GRV Dynamic volumes calculated using D material balance equations and in D using MoRes software z Ax N A4 A9 A7 z A7z A Az A A0 Ay B4a B 0 B 6 B 4

19 Results Targets, Risks and Uncertainties Portfolio of targets; each with a range of recoverable volumes and associated risk High Case Base Case Low Case x z Ax A 4 A 9 z Smaller recoverable volumes ~-4 MMbbls A7z A Az A7 A A0 4 Ay B4a B 0 B B Larger recoverable volumes ~- MMbbls 6 9

20 Results Targets, Risks and Uncertainties Portfolio of targets; each with a range of recoverable volumes and associated risk Targets further sub-divided into three sets: Target set : Recoverable volume is expected to be drained by current wells Target set : Recoverable volume can be drained by well intervention/ reservoir management Target set : Recoverable volume requires new well(s) to be drained optimally x z Ax A4 z Larger recoverable volumes ~- MMbbls Smaller recoverable volumes ~-4 MMbbls A9 A7z A Az A7 A A0 4 Ay B4a B 0 B 6 B 0

21 Operations #: A0 Recompletion Recompletion of A0 - March 00 A0 was drilled in 00 with the objective to appraise South Pierce Chalk (Ekofisk and Tor) Well intervention to re-perf the Forties Sandstone A7z A A0 A 9 Az Another gas injector can potential increase production in the South Pierce area and alleviate gassed out wells in North Pierce. AY South Pierce z Well section re-perfed in Forties SST B B 0 B Surface displayed: Base Forties

22 Operations #: B New Drill New Drill Well B July 00 Targeting attic volumes up-dip of watered out B well A0z 4 Integrated approach very valuable as this strategy goes against traditional Pierce Ay South Pierce wells Well location very sensitive to GOC and z previous well depletion integration between RE and WE very important East of South Pierce shown to be B B B B unattractive allows a shorter, more efficient well to be drilled Risk: Early gas breakthrough Mitigation: Maintain stand-off to gas cap, monitor well while drilling and manage reservoir using South Pierce s two gas 6 KEY E&A Well Oil Producer Water Injector Gas Injector Fault injectors

23 Operations #: NNP Development New Well(s) in North of North Pierce area - Summer 0 Option Second largest target identified by the locate the remaining oil work x Still in concept design phase, deciding most appropriate number, type and location of wells Development is complicated by distance from main drill site, thus requiring expensive hook-up planning required multidiscipline integration from day z Option Ax North Pierce A4 A9 Option A6 z MDS A7

24 Summary Integrated team can provide robust infill well targets and workover opportunities: Identified ~ 60 MMbbls scope for recovery As a result of the LTRO work; new well to be drilled in June 00 and further infill-wells in the drill sequence for 0 LTRO work has indicated that the current field recovery factor can be improved from 4% to 0% provided we can recover the LTRO work s base case

25 Acknowledgements The authors would like to acknowledge the Pierce partners Summit Petroleum and NOEX for their permission to publish. The authors would like to thank the Pierce team for their input and hard work during this project.

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