AOGCC OKs Prudhoe satellite rules changes

Petroleum News

The Alaska Oil and Gas Conservation Commission has approved Prudhoe Bay satellite pool rules changes requested by operator BP Exploration (Alaska) Inc. “to bring conformity and consistency to the well testing requirements and pressure survey requirements” of satellite fields at Prudhoe, improving field management efficiency for BP and compliance oversight for the commission, the commission said in its administrative approval.

The changes were requested in October for the Midnight Sun, Aurora, Borealis, Polaris and Schrader Bluff oil pools; the commission approved rules changes May 29.

Well testing, required once a month for each Prudhoe well, was required at least twice a month during the first three months of production for satellites. BP told the commission that all the satellites are well established and the need for increased well testing in early production no longer exists. Elimination of the multiple-well-test requirement would also promote efficiency at the drill sites in Prudhoe which produce from more than one pool.

Another inconsistency was in required pressure surveys, with Aurora, Borealis, Orion and Polaris rules requiring an initial pressure survey in each new well before regular production begins, while reliable estimates of pressure can be obtained from the pore pressure survey fluid gradient study conducted prior to drilling each new wellbore and from reservoir response during drilling. There are also reservoir models in place and years of development in the Prudhoe pools, making collection of pressure survey data on new wellbores unnecessary for proper pool development.

With a uniform approach to reservoir pressure monitoring, more useful information available.

For the Aurora and Orion pools, the rules relate required pressure surveys to governmental sections in the pool, while pool rules for other satellite pools completed in the same formations do not have that requirement.

An annual proposed reservoir pressure survey program for each pool provides AOGCC with sufficient information. “At the minimum,” the commission’s order says, “AOGCC will collect at least one pressure survey per active representative area sufficient to ensure that an adequate reservoir pressure survey program is conducted in these pools.”

Also, changing Aurora pressure survey results requirements from quarterly to annually will bring that pool’s reporting requirements into conformance with the rest of the field.

The commission noted that the pool rules affected have administrative approval clauses allowing rules to be administratively amended “as long as the change does not promote waste or jeopardize correlative rights, is based on sound engineering and geoscience principles, and will not result in an increased risk of fluid movement into freshwater. The AOGCC finds that these conditions are met and that the orders may be administratively amended.”