Disposal injection approved at Nicolai Creek field

Petroleum News Alaska Staff

The Alaska Oil and Gas Conservation Commission has approved an application from Aurora Gas LLC for underground injection of oil field wastes at Nicolai Creek.

The commission said that Aurora requested authorization in February to dispose of non-hazardous Class II oil field waste fluids into the Tyonek formation at Nicolai Creek on the west side of Cook Inlet.

In a June 26 order the commission authorized underground disposal between 2,000 feet and 2,550 feet measured depth in the Nicolai Creek Unit No. 5 well, a vertical well on federal lease AA-8426, administered by the Bureau of Land Management. Cook Inlet Region Inc. is the surface owner.

Aurora proposes to re-enter the well, drill out the surface plug and clean up the casing to a depth of 2,500 feet. The well will be completed with 2-7/8 inch tubing and a packer at approximately 2,250 feet. Perforations will be added between 2,325 feet and 2,345 feet.

The commission said the disposal waste stream will consist of produced water; drilling, completion and workover fluids; drill cuttings; rig wash; mud slurries; and other Class II fluids and solids. The composition of the waste stream and volumes will very depending on drilling, workover, stimulation and maintenance activity. An injection pump will be continuously manned during injection operations and the annulus pressure of the well will be checked and recorded prior to and after each injection cycle.

Aurora estimates that the average daily injection volume will range from 350 to 1,000 barrels at rates ranging up to a maximum of five barrels per minute depending on the number of producing wells, drilling activity and well work.