Marathon working to re-establish gas production at Spark platform

Company says it is committed to bringing platform back on line in Cook Inlet’s North Trading Bay unit; Unocal working interest partner

Kristen Nelson

PNA Editor-in-Chief

Marathon Oil Co. told the state in early October that it is in the process of formulating a plan to re-establish gas production from the Spark platform in Cook Inlet, lost in March 2000 after the one producing well on the platform, the S-2rd, shut-in due to excessive water production.

A company representative told PNA Nov. 6 that Marathon is in the “conceptual phase” of a project plan to get natural gas production from Spark flowing.

The company said in its 30th plan of development and operations for the North Trading Bay unit that its plan for 2003 includes both the gas sands and the Hemlock oil reservoir. Marathon said it and its working interest partner, Unocal, “are committed to finding the most economic means to maximize recovery of NTBU gas reserves in a timely manner.”

The Spark platform is one of two in the North Trading Bay unit. Volumetric calculations, the company said, indicate 27 billion cubic feet of original gas in place in eight sands. Two wells have produced 5.1 bcf.

Facilities at North Trading Bay, built for oil production, include the Spark platform, the Spurr platform (formerly Texaco “A”) and the Grant Point production facility.

Spark platform oil production was shut in on Jan. 26, 1992, and Spurr platform oil production was shut in on July 16, 1992. The production facility has been inactive since the July 1992 shut-in of final oil production.

The installation of gas production facilities on the Spark platform was completed in the fall of 1996, Marathon said, and gas production began in December 1996.

Two-hour test in August

During 2002 the Spark gas well S-2rd was produced one day, for a two-hour well test on Aug. 2. Marathon said the test was manually assisted and “demonstrated that gas sales should be viable with a surface facility upgrade.”

Surface or downhole remedial actions will be required to reduce water production and enhance disposal prior to resuming gas production, the company said. Modification of the surface facilities on the Spark platform for gas sales and water disposal are planned for 2003, and Marathon said that continued intermittent well tests will be needed to assist in designing the facility modifications. Gas production facilities on the Spark platform are designed for unmanned operations, Marathon said. The living quarters on Spark have been decommissioned and production is handled by radio telemetry from Marathon’s Kenai gas field.