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AOGCC approves Prudhoe, Put River production downhole commingling
Ruling allows production of some 6.9 million barrels of oil in place in Put River, above Prudhoe, which would otherwise be stranded Kristen Nelson Petroleum News
The Alaska Oil and Gas Conservation Commission has approved a June request from Prudhoe Bay field operator BP Exploration (Alaska) to allow for commingled downhole production for wells completed in both the Put River and Prudhoe oil pools.
The Prudhoe oil pool has been in production since 1977, the commission said, with wells generally very productive due to high-quality reservoir rocks.
Put River overlies the Prudhoe oil pool and consists of three lobes - Central, Southern and Western - of the Put River sandstone, with a fourth lobe, the Northern, in hydraulic communication with the Prudhoe oil pool and included as part of the Prudhoe pool.
The Southern lobe of Put River has been in somewhat regular production since 1999 with an active waterflood. 2005 appraisal activities identified oil and gas condensate in the Western and Central lobes, respectively, the commission said, “bur further development was not pursued at that time in part due to low flowrates that resulted in operational challenges associated with hydrate deposition.”
The Central lobe contains an estimated 1.1 million to 2.7 million barrels of oil in place and the Western lobe contains an estimated 69.6 billion to 104.4 billion cubic feet in place with a condensate yield of approximately 40 barrels per million cubic feet, with a condensate in place value of between 2.8 million and 4.2 million barrels of oil.
Trapped reserves The commission said Dec. 13 in revisions to conservation orders for the two oil pools that several wells penetrating the Prudhoe and Put River oil pools would be candidates for downhole commingling, which “should allow for increased flowrates and flow velocity in the tubing and reduce the potential for the hydrate deposition that is problematic in production from wells completed solely in the (Put River oil pool). Since standalone production of the Central and Western Lobes is not viable due to hydrate deposition those reserves are essentially trapped. Commingling of production with the (Prudhoe oil pool) will allow these resources to be recovered.”
Commingling of production between the Prudhoe and Put River oil pools should allow for development of up to 6.9 million barrels of hydrocarbon liquids in place within the Put River oil pool “that would not be recoverable as a standalone development,” the commission said.
Commission data show that the Prudhoe oil pool has produced 11.9 billion barrels through October, the latest data available, while Put River has produced 3.1 million barrels.
Total production from the Prudhoe Bay field - the Prudhoe oil pool and all other pools at Prudhoe combined - is more than 12.8 billion barrels through October.
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