Unocal begins first West Seno deepwater oil production off Indonesia

Aug. 21, 2003
Unocal Corp. said Wednesday that its Unocal Makassar Ltd., subsidiary has begun oil production in conjunction with Phase 1 of the company's deepwater West Seno project off East Kalimantan, Indonesia. "First oil from West Seno reached the Santan onshore terminal (on Kalimantan) on Aug.17, Indonesia Independence Day."

By OGJ editors

HOUSTON, Aug. 21 -- Unocal Corp. said Wednesday that its Unocal Makassar Ltd., subsidiary has begun oil production in conjunction with Phase 1 of the company's deepwater West Seno project off East Kalimantan, Indonesia.

"First oil from West Seno reached the Santan onshore terminal (on Kalimantan) on Aug.17, Indonesia Independence Day," Unocal said.

West Seno is the first deepwater oil and gas project off Indonesia. The field is in 975 m of water in the Makassar Strait between Kalimantan and Sulawesi, about 190 km northeast of Balikpapan.

Unocal currently is producing 14,000 b/d of oil and 18 MMcfd of gas from the first four wells put on production from West Seno. The fifth well will be put on production within a week to bring production to more than 17,000 b/d.

Gross production from Phase 1 is expected to reach 35,000-40,000 b/d by yearend, as more wells are completed, with additional production expected in 2004 as development drilling continues, Unocal said. The company plans ultimately to have 48-52 wells in the field (OGJ Online, Sept. 25, 2001).

Continuing development
Unocal is developing West Seno in two phases with two tension leg platforms (TLP) and a floating production unit (FPU). Phase 1 includes 28 development wells to recover resources in the northern section of the field. The TLP supports the wells and a tender-assisted drilling rig. This is the first application of a tender-assisted drilling rig in a deepwater environment. The TLP is linked to the nearby FPU where the produced oil and gas is processed to sales quality.

Phase 2 will include a second TLP and up to 24 additional development wells on the field's southern section. Daily production is expected to peak at 60,000 bbl of oil and 150 MMcfd of gas by yearend 2005 with the completion of Phase 2 development.

Unocal ultimately expects to recover 210-320 million boe from West Seno.

Unocal Makassar operates the production-sharing contract and has a 90% working interest. Pertamina Upstream, a unit of the state-owned oil and gas company, holds the remaining interest.

Unocal said it also has recorded several potentially commercial deepwater discoveries off East Kalimantan that are expected to come on line in the next several years. These discoveries include significant gas resources that could supply as much as 40% of the needs of the Bontang LNG plant, one of the world's largest (see photo OGJ, Mar. 4, 2002, p. 56).