Harding Field: Life Extension of Oil Production in a Low Gas Price World

Transcription

1 Harding Field: Life Extension of Oil Production in a Low Gas Price World Pinggang Zhang 1, Steve Green 1, Andrew Sharpe 2 1. BP, 2. Baker-RDS 13 May 2010

2 Contents Field overview and the challenge New strategy and approaches Result A typical infill well Summary Learnings Acknowledgement hole picking prize

3 BEST_GP.DT_1 140 US/F 40 BEST_GP.CALI_1 6 IN 16 BEST_GP.GR_1 0 GAPI 150 WELL: 9_23B-7 SCALE: 1:500 Balder Balder Injected Sand Balder Massive Sand Lower Balder Sele TVD FEET Depth FEET BEST_GP.DRHO_1 BEST_GP.VSH_1-0.4 G/C V/V 1 BEST_GP.RHOB_1 BEST_GP.ILD_1 CORE.CPOR_CORE_1 CORE.CKHG_CORE_1 BEST_GP.SW_ G/C OHMM V/V MD V/V 0 BEST_GP.NPHI_1 BEST_GP.ILM_1 CA.CPOR_CA_1 CA.CKHL_CA_1 CALC.PHIE_2 45 V/V OHMM V/V MD V/V 0 Field Overview Location Initial Fluids Distribution NNE Sand quality: 10+D Central SE Injected Sand Complex South Balder Massive Sand Fluids Property Oil: µ oil: 10cp, 19 o API, GOR: 238scf/bbls Development Jackup platform development since 1996

4 The Challenge Harding in 2007 Achieved 70% oil recovery factor in Harding Central Perceived to have run out of oil targets COP was due 2010 Surveillance stopped Major gas development planned The gas project delayed due to low gas price Baseline st 2nd 4D 4D 3rd 4D COP Harding Gas Base platform turndown limit COP The Challenge 10 0 Could we keep the platform running longer and improve recovery factor even further? logging for GOC

5 New Strategy and Approaches New strategy: to chase oil Infill targets, normally small and risky Reservoir management optimisation Approaches new surveillance TDRM TM Infill Opt TDRM TM critical hist. data review Res Opt multiple models with big range of uncertainties 4D seismic single deterministic model with small range of uncertainties TDRM TM is a trademark of Top Down Reservoir Modelling

6 Results 5-well infill program proposed to target oil in the initial gas cap, attic oil and satellite pools Reservoir management strategy changed and the oil increase confirmed Reserves increased, mainly from infill. Oil rate doubled compared to base. Life of the field extended by at least 4 years, more options are being worked. YE2007 Reserves R eserves add component evolution (mmstb) produced in 2008 YE2008 produced in 2009 YE2009 production rate (mboe/d) Economic cutoff?? mbd Harding Gas DS NNE IC6 IS5 Base notional blowdown Timing:

7 An Example of a Typical Infill Well 1/8 The infill target Currently no producer in NW corner Previous deeper well watered out Oil has migrated to initial gas cap A little challenge How can we confirm the oil is in the gas cap? What are the main uncertainties? A IS5 IS5 A water injector oil producer

8 An Example of a Typical Infill Well 2/8 Critical production log review confirmed the possibility of oil migration to gas cap Simulation model matched this GOC movement Sorg and Sgtr evaluated here increased confidence in sim model Data discarded in 1998 was then considered critical for oil well placement in gas cap Residual oil saturation due to gas sweep evaluated here Trapped gas saturation evaluated here

9 An Example of a Typical Infill Well 3/8 4D seismic also showed the oil move to gas cap Simulation model match to GOC loggings (right) and 4D seismic interpretation (below) 4D match Logged gas oil contacts Sim x-seciton GOC 4D surface GOC 4D surface view from above the 4D GOC surface view from below the 4D GOC surface

10 An Example of a Typical Infill Well 4/8 Main uncertainties and mitigations base impact mitigations oil column thickness 80ft 0.5 mmstb/10ft pilot holes well landout depth 30ft from GOC 1.0 mmstb/10ft relative to pilot hole result gas threat at toe horizontal well earlier gas out 10 deeper@toe

11 An Example of a Typical Infill Well 5/8 Real time seismic tie while drilling (pilot hole) North South Upper Injection Wing GR A30 Top Balder Formation Depth (m) Depth (m) Top Balder Massive Sands Mistie probably due to seismic migration issue with dipping structure (in other orientation) A30 GOC 2005 GOC (from 4D) Fault 2005 OWC (from 4D) 1990 Coloured Inversion Depth Seismic, D Processing Base Balder Massive Sands

12 An Example of a Typical Infill Well 6/8 - Pilot Hole Results Min. oil column ~73ft TVD ML oil column ~80ft TVD GR Neutron TVDSS Density Resistivity Top Massive Sand Gas-Oil Contact Sgtr = 33% MWD tool failure whilst in reservoir Resistivity decreasing near base of log - close to oil-water contact? Min. Oil

13 An Example of a Typical Infill Well 6/8 - Mainbore landout North South Fault Intra-Horda Seismic Marker GR A30z (IS5) Top Balder Formation Depth (m) Upper Injection Wing A30 GOC GOC (2.5m shallower than A30) Top Balder Massive Sands Actual top massive sand Heel 655m near horizontal section 1990 Coloured Inversion Depth Seismic, D Processing Base Balder Massive Sands Toe 3m deeper than heel

14 An Example of a Typical Infill Well 8/8 - Production Oil rate is on prognosis and currently dry. GOR is still around solution GOR BHP is stable 350 IS5z scf/bbl & w/c Watercut GOR Oil Rate DHPG psig & oil rate Feb Feb Mar Mar Mar Apr Apr-10

15 Summary The life of a very mature field, even at 70% recovery, has been extended for at least 4 years when gas price was too low. The workflow of a typical infill example to chase oil in gas cap has been demonstrated. The integration of log, seismic and production data is the key to understand the remaining oil distribution.

16 Learnings Late life potential, even at 70% recovery factor, may be underestimated. Is there a prize hidden within your uncertainty? Can you target the surveillance to define the prize? Are there other evidence to support your prize? TDRM TM revealed the Harding late life development, as it provided a quick way to identify the critical surveillance calibrate the reservoir model, and evaluate business options. Coviz provided a powerful way for data integration G&G, RE, Petrophysics TDRM TM

17 Acknowledgement Colleagues involved in realising the Harding life of the field extension. Colleagues for their original contribution to this presentation Steve Green, Andrew Sharpe BP North Sea and the partner Maersk Oil and Gas for permission to present this material.