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Alaska Oil and Gas Conservation Commission

Alaska Department of Administration, Alaska Oil and Gas Conservation Commission
Administration >  AOGCC >  Statistical Reports >  Annual Pool Statistics - 2004 >  Kuparuk River Unit, Tabasco Oil Pool
AOGCC Pool Statistics
Kuparuk River Unit, Tabasco Oil Pool
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Operator: ConocoPhillips Alaska, Inc.
Discovery Well: ARCO Alaska, Inc.
  Kuparuk River Unit 2T-201
  Permit #195-122
  API No. 50-029-20230-00-00
  Sec. 1, T11N, R08E, UM

Depth: 4,175’ MD / 3,832' TVD

September 28, 1995
Status: Producing
Location: Central Arctic Slope Area Location Map PA Location Map DNR Unit Map
Orders: Complete List
Summary:
The Tabasco Oil Pool is one of the satellite pools that have been discovered and developed utilizing Kuparuk River Unit (“KRU”) infrastructure.  The pool was discovered in 1986 during development drilling of the underlying Kuparuk River Oil Pool from the KRU 2T-Pad.  The Tabasco Sandstone underlies a large portion of the southern and western KRU.  Producible hydrocarbons were encountered in the Tabasco Sandstone between 3,352’ to 3,599’ measured depth (“MD”) in the KRU 2T-201 well.  The Tabasco pool lies at approximately 3,000’ true vertical depth subsea (“TVDSS”), about 300’ to 400’ below the West Sak sands.  Tabasco oil has an API gravity of 16 degrees, and it is highly viscous (253 centipoise).  No definitive oil-water contacts have been delineated within pool.  Original oil in place (“OOIP”) for the 2T-Pad area is projected at 48 to 131 million barrels of oil (“MMSTB”).  A small gas cap of about 32 acres occurs in the 2T-201 area, with the gas-oil contact at 2,915’ TVDSS.  The gas cap contains an estimated 100 MMSCF of gas in place, but is not expected to have a major impact on reservoir performance.  Regular production began in April of 1998.  Production peaked in May 1999 at an average of 7,913 barrels of oil per day (“BOPD”), and declined to 5,227 BOPD in December 2004.

Geology:
The Tabasco Sandstone is an informal member of the Late Cretaceous-aged (Campanian) Schrader Bluff Formation. It was deposited near a shelf margin as a prograding sequence of deltaic to near shore marine sediments. The sandstone is discontinuously distributed over a broad region, with sand thickness generally most significant along the shelf margin.  Large-scale slumping and erosion are common.  Two lithologies are present: a discontinuous thin-bedded sandstone facies with shale interbeds and an overlying amalgamated sandstone facies.   The thin-bedded sandstone facies is more widespread; its gross interval thickness is about 80’ to 400’.  The amalgamated sandstone facies ranges in thickness between 45’ to 350’ thick. The transition between the two facies is abrupt. Porosity ranges from 17 to 22% and averages 20%. Log water saturation ranges from 17 to 60%, with 20 to 25% representative of the 2T-Pad area.  Pressure transient permeability ranges from 3 to 100 Darcies. The Tabasco structure is a monocline, dipping east to northeast and striking north to northwest in the western portion of the KRU and east to southeast in the southern portion. The hydrocarbon-trapping mechanism is a combination of stratigraphic and structural elements. The Tabasco accumulation is cut by a series of north-south and east-west normal faults, with throws typically ranging between 10’ to 50’ and maximum throws to 100’. Oil distribution appears controlled by the stratigraphic distribution of reservoir sands.

Strat Column
Orig. Oil in Place: 48 to 131 MMSTB (CO 435)
Production: Prod Chart Prod Report Prod Data

  Oil (bbls) NGL (bbls) Gas (mcf) Water (bbls)
Cumulative 9,735,474
0 1,328,980 26,189,706
2001 Total 1,317,558 0 180,047 4,357,006
2002 Total 1,089,001 0 158,610 5,408,990
2003 Total 1,541,615 0 187,877 4,864,655
2004 Total 1,472,323 0 182,459 5,749,828
2003 Daily Rate 4,278 0 515 13,328
2004 Daily Rate 4,034 0 500 15,753
Change (%) -6% 0 -3% 18%

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