Watching the WorldHP-HT prospects

Sept. 13, 1999
The Elgin-Franklin gas-condensate fields development in the U.K. North Sea marks the end of one era but acts as a pointer to another.

The Elgin-Franklin gas-condensate fields development in the U.K. North Sea marks the end of one era but acts as a pointer to another.

The production utilities and quarters jack up being built by Brown & Root McDermott Fabricators Ltd., Nigg, Scotland, is expected to be the last giant platform used in a U.K. North Sea project.

The 40,000 metric ton platform is due to be floated out of Nigg in March 2000, with a view to bringing Elgin and Franklin, which comprise the world's largest high-pressure, high-temperature development, on stream during the summer (OGJ, June 21, 1999, p. 18).

Elgin-Franklin pushes the boundaries of HP-HT technology and is expected to help operator Elf Exploration U.K. plc establish itself as a leading player in the exclusive club of HP-HT expert companies.

Joel Fort, director of the Elgin-Franklin project at Elf, told OGJ that HP-HT field development will become increasingly significant as many countries revisit old plays with new exploration techniques.

Niche technology

HP-HT is viewed as a niche for the time being, but in the future, the re-exploration of old plays is expected to boost the number of HP-HT prospects from the present small number.

For example, Mexico has HP-HT finds that have not been developed, and so has the Gulf of Mexico. Meanwhile, Elf is considering satellite prospects near Elgin-Franklin.

Elf discovered Glenelg, formerly called West Elgin, in March. Glenelg reserves are estimated at 100 million boe of gas and condensate.

The find is being considered for development as a subsea satellite, but Fort said 15,000-psi subsea trees would need to be developed before the project could happen.

Glenelg is tentatively scheduled for development in 2003-04, and Fort said other nearby finds could be exploited using the facilities at Elgin-Franklin or the linked Shearwater field, being develop in parallel by Shell U.K. Exploration & Production.

Shell originally intended to develop the Puffin discovery along with Shearwater but shelved it instead. This is still being considered for development as a Shearwater satellite.

Meanwhile, BP Amoco plc has a nearby discovery called Kessog, to the southeast of Elgin-Franklin, which Fort said could be developed as a satellite, although its pressure and temperature are not so onerous. Other finds in the area were said to be marginal.

Triassic well

But Elf may have another record-breaking project about 500 m below the Elgin-Franklin reservoir. Fort said the Santa Fe Magellan jack up rig has been fitted with a 20,000-psi blow-out preventer and choke manifold ready to drill the Triassic formation at a depth of 6,500 m.

Fort said the Triassic prospect is large enough to contain reserves of 150 million boe. The formation is expected to be at a temperature of 235? C. and a pressure of 1,350 bar.

"To produce the Triassic there would be nothing available off the shelf," said Fort, "but we believe we are close enough to these conditions to say that, if we find something large enough to develop, our service companies are clever enough to find a way."