Unocal details offshore Indonesia drilling results

Recent Drilling On Makassar Strait PCS [145,910 bytes]

Unocal Corp. has revealed the results of its continuing development drilling program in the deepwater Seno structure off East Kalimantan, Indonesia.

Undaunted by low oil prices, the company has decided to pursue fast-track development of West Seno oil and gas field. Unocal Indonesia Co. and partner Mobil Makassar Inc. expect to submit a detailed development plan to state firm Pertamina early in the second quarter.

West Seno is the first deepwater field the partners will develop off East Kalimantan. It is one of several prospective areas on the greater Seno structure in the Kutei basin.

Drilling to date

Recent drilling in the Makassar Strait production-sharing contract (PSC) area, where most of the Seno structure lies, has included six wells in West Seno and two each in East Seno and South Seno (see map). Another well is drilling ahead on the nearby Janaka prospect.

Details of the wells are shown in the Table 1 [78,783 bytes]

Unocal's latest West Seno delineation well, West Seno 4, has thus far cut 319 ft of oil and gas pay and is still drilling.

"Based on the successful exploration and delineation drilling to date, the company estimates gross recoverable oil and gas resources for the West Seno field alone at about 150 million boe," said Unocal.

Unocal's first well on the Janaka prospect, 10 miles south of Seno in the Makassar Strait PSC, cut 39 ft of confirmed oil and gas pay and 54 ft of probable pay.

"If subsequent drilling on Janaka proves commerciality," said Unocal, "the field could be developed in concert with other Makassar Strait projects."

In addition, Unocal says its Merah Besar field, which straddles the boundary between the East Kalimantan and Makassar Strait PSCs, could be developed as a satellite to West Seno.

Production from the deepwater Seno and Merah Besar fields is expected to begin in 2001.

Forging ahead

Unocal plans to continue its aggressive drilling program in the Kutei basin, with 20-25 deepwater exploration and delineation wells planned for 1999 alone.

The company has identified five prospects on the Makassar Strait and Rapak PSCs, within 9 miles of Seno, that it considers attractive and ready to drill. In addition, it has identified "dozens of additional leads" to be evaluated on these PSCs.

"Our early success with this exploration program has given us the enviable challenge of balancing additional exploration with development of our discoveries," said Unocal Indonesia Pres. Timothy C. Lauer.

"Our goal in this low-price environment is to move forward with innovative, low-cost developments," said Lauer. "Based on resource size, both proven and potential, the greater Seno structure has moved to the front of the queue in our development portfolio and will be Unocal's first deepwater development in Indonesia."

Unocal Chairman and CEO Roger C. Beach said, "Our continued success and expanded knowledge of the geology have increased our confidence and enthusiasm for this deepwater area in Indonesia. We continue to see outstanding reservoir quality and high-grade oil resources throughout the basin."

Unocal Makassar Ltd. is operator of the Makassar Strait PSC and owns a 50% working interest, while Mobil Makassar holds the remaining 50%. Unocal Indonesia is operator and 100% working interest holder in the East Kalimantan PSC.

Unocal Rapak Ltd. is operator of the Rapak PSC and owns a 70% working interest, while Mobil owns the remaining 30%.