Boulton first gas tops U.K. North Sea action

Conoco (U.K.) Ltd. claims gas flow in Boulton field, brought on stream on Jan. 28, is the highest sustained rate for a Carboniferous well in the southern U.K. North Sea.

In other action, Shell U.K. Exploration & Production intends to study development prospects for an "exciting" gas/condensate find in the Outer Moray Firth area off northeastern Scotland.

Meanwhile, BP Exploration Operating Co. Ltd. has begun decommissioning work in U.K. North Sea Donan field, developed with a production ship and two subsea wellheads.

Boulton

Conoco developed Block 44/21a Boulton field with an unmanned platform tied back to Murdoch platform 11 km to the east for processing and export.

The operator said the first of the field's two planned production wells is currently yielding 114 MMcfd of gas, which is expected to be peak output. The second well is intended to be a dual-lateral into a separate reservoir.

Boulton reserves are estimated at 165 bcf of wet gas, and field life is anticipated to be 17 years. The reservoir lies at a depth of 4,000 m and was discovered in 1984.

Conoco said the platform jacket is based on a design by Atlantia Corp., Houston, for the Gulf of Mexico. The jacket has production risers inside its legs, to protect the wells and reduce wind and wave action loads on the jacket.

The jacket weighs 450 metric tons and stand 57 m high, with a 400-ton deck. It has four legs and capacity to accommodate four wells.

The platform is controlled remotely from Conoco's Theddlethorpe terminal control room.

Boulton field interest holders are operator Conoco 46%, Lasmo North Sea plc 44.5%, and British-Borneo Petroleum Syndicate plc 9.5%.

Conoco's share of produced gas will be added to its portfolio for supply to customers directly. Lasmo and British-Borneo have sold their shares to independent Eastern Natural Gas (Trading) Ltd.

Goldeneye

Shell Expro, operating joint venture of Shell U.K. Ltd. and Esso Exploration & Production U.K. Ltd., has provisionally named its Block 14/29a find Goldeneye.

The find was made with the 14/29a-3 new-pool wildcat drilled late in 1996. Shell/Esso was scheduled to complete appraisal well 14/29a-4, drilled to the east of the discovery well with Borgny Dolphin semisubmersible rig, by the end of January.

Shell said the discovery well cut a potentially commercial gas/condensate reservoir in a lower Cretaceous formation. The well flowed at a rate of 22 MMcfd of gas on test, restricted by surface equipment.

Goldeneye extension

Meanwhile, operator Shell reports that Amerada Hess Ltd. has confirmed that the Goldeneye structure extends into the block immediately to the south by drilling 20/4b-6 exploration well, which has not yet been tested.

Shell/Esso and Amerada have agreed to share evaluation results from the two wells and to jointly analyze high-resolution 3D seismic data acquired by Shell/Esso over the structure in summer 1997.

The two operators are considering a joint development of Goldeneye, although a Shell official said it is too early to have firm ideas about development plans. A major consideration is export of gas from an area with no processing infrastructure.

The official said Shell and Amerada's cooperation on Goldeneye is based on lessons learned in Bittern and Guillemot West fields, currently under development with a shared floater (OGJ, Nov. 17, 1997, p. 31).

"Shell and Amerada had both discovered part of Bittern, calling it Razorbill and Abbot, respectively," said the official. "We learned from this project the benefits of getting people around a table to discuss a cooperative development."

Donan

BP was working to dismantle production systems in Block 15/20 Donan field even as the U.K. Department of Trade and Industry announced approval of the decommissioning plan.

The field was brought on stream in 1992 with the Seillean production, storage, and offloading ship moored in 140 m of water. Donan's reserves were estimated at 15 million bbl of oil.

BP's Single Well Oil Production System wellhead design, intended for use in marginal field developments, was used for both the Donan wells. When the field was brought on stream, BP owned the Seillean.

BP sold Seillean in 1996 to Reading & Bates (U.K.) Ltd., Aberdeen. The vessel is currently docked in Invergordon, Scotland, and is being considered for use in development of Block 22/2a Chestnut discovery by Premier Oil plc.

At presstime, BP was waiting on weather to begin recovery of the two wellheads and control umbilicals, with Stena Seawell construction ship. Seabed equipment will be completely removed for re-use, recycling or disposal.