Marathon Oil U.K. Ltd. plans to develop Beinn gas/condesate field in North Sea Block 16/7a with as many as four producing wells drilled from nearby North Brae field.
Marathon submitted a development plan to the 1-7.K. Department of Trade and Industry. Beinn reserves are estimated at 150 bcf of gas and 20 million bbl of condensate. Development cost is about $1/bbl oil equivalent under the plan.
Beinn field was discovered in 1987 in middle Jurassic sands partly underlying North Brae upper Jurassic field.
Marathon's Beinn 16/7a-30z discovery well was reentered in 1989 for testing. It flowed 12.9 MMcfd of gas and 1,319 b/d of condensate with 2,080 psi flowing tubing pressure.
The first Beinn field appraisal well, 16/7a-B20, was drilled last year from the Brae B platform over the North Brae reservoir and completed in a 230 ft middle Jurassic reservoir.
The well, on extended production test since December 1992, had produced 7 bcf of gas and 1 million bbl of condensate by the end of last month. Current production is 24 MMcfd of gas and 3,400 b/d of condensate.
A second Beinn appraisal well, 16/7a-B21, was drilled this year and confirmed 220 ft of middle Jurassic pay before completion in an upper Jurassic zone. The well is on production test and is expected to be recompleted in the middle Jurassic by mid-1994.
WHAT'S NEXT
Marathon plans to drill a Beinn development well and conduct a 3D seismic survey of the field next year. A further development well may also be spudded. Production start-up is slated for 1994.
In December Marathon intends to place on stream East Brae field in Block 16/3a. Development cost is pegged at 867 million ($1.3 billion). East Brae reserves are estimated at 1.5 tcf of gas and 300 million bbl of liquids.
East Brae platform holds gas processing and export facilities, which will be used to deplete Brae gas reserves along with East Brae. Gas from Brae fields has so far been reinjected and used for power generation on Brae A and Brae B platforms.
Starting in October 1994 about 270 MMcfd gas from the four Brae fields will be sent 15 miles to join the Scottish Area Gas Evacuation (SAGE) pipeline to St. Fergus, Scotland. Production will be stepped up to 350 MMcfd in 2003.
Another potential development on Block 16/7a is West Brae field, is said by Wood Mackenzie Consultants Ltd., Edinburgh, to hold reserves of 50 bcf of gas and 15 million bbl of oil. The analyst expects West Brae to be a subsea development tied back to Brae A platform. Start of production is slated for 1996.
Commenting on Beinn field development, John Parziale, president of Marathon U.K., said, "We are enthusiastic about the economics of this project. Thanks to the cost advantage provided by our existing infrastructure, Beinn reserves can be developed at about $1/bbl of oil equivalent."
Beinn field will be developed by the Brae Group, made up of operator Marathon 38%, BP Exploration Operating Co. Ltd. 20%, Bow Valley Petroleum (U.K.) Ltd. 14%, Kerr-McGee Oil (U.K.) plc 8%, British Gas plc 7.7%, Louisiana Land & Exploration Co. 6.3%, Neste Production Ltd. 4%, and British-Borneo Oil & Gas Ltd. 2%.
The Brae area went on stream in July 1983 from the A platform in South Brae field. Central Brae field was placed on stream in September 1989 as a subsea tie-back to Brae A platform.
Block 16/7a Brae field original reserves are estimated at 840 bcf of gas and 565 million bbl of liquids.
Wood Mackenzie estimates production from Brae A, Brae B, and Central Brae at an average 11,000 b/d, 37,000 b/d, and 13,000 b/d respectively in the year to the end of last September.
