Two New Unocal Deepwater Discoveries in Indonesia
Unocal Corp. has discovered oil and gas in the Bangka and Aton prospects in the Rapak Production Sharing Contract (PSC) deepwater area offshore Indonesia, further confirming that the company's Kutei Basin deepwater properties have significant hydrocarbon resource potential.The Bangka discovery is located nine miles (14 km) north of the West Seno Field. The Bangka #2 well was drilled to a depth of 9,752 ft (2,972 meters) in 3,191 ft (972 meters) of water and encountered 367 net ft (112 meters) of liquid-rich gas pay in the Upper Miocene. The Bangka #2 pay is confined to two zones of high-quality reservoir rock with hydrocarbon columns calculated to be greater than 500 ft (152 meters). The follow-up Bangka #4 well was drilled down-structure in 3,234 ft (986 meters) of water to a depth of 11,656 ft (3,553 meters) and encountered significant thickness reservoir sands, including 38 ft (12 meters) of net oil and gas pay. The Bangka #5 well, located 3.5 miles (5.6 km) northwest of the Bangka #2 well, is currently being drilled.
The Aton discovery is located 5 miles (8 km) southeast of the Bangka #2 well. The Aton #3 well was drilled to a depth of 8,465 ft (2,580 meters) in 3,826 ft (1,166 meters) of water and encountered 255 ft (77 meters) of high quality reservoir and 80 ft (24 meters) of oil and gas pay. A follow-up well, the Aton #1, was drilled to a depth of 12,465 ft (3, 800 meters) in 3,644 ft (1,111 meters) of water and encountered significant reservoir sands and 59 ft (18 meters) of net oil and gas pay in two zones.
"The Bangka and Aton discoveries are the result of the integration of the data from earlier wells and attest to the evolving understanding of the deepwater exploration play," said Brian W. G. Marcotte, president and general manager of Unocal Indonesia Co. "We think we have found an important key for exploring in the Upper Miocene, and we are much more confident in our ability to predict the occurrence of significant sand accumulation in the area."
Marcotte noted that an additional 300 square miles (800 sq km) of new 3D seismic data will be available before the end of the year.
Unocal has now made five deepwater Upper Miocene oil and gas discoveries offshore Indonesia since beginning its exploration program in 1998. Two of the discoveries, Merah Besar and West Seno, have received approval from Pertamina for Plans of Development.
The commercial potential of the other three discoveries—Janaka North, Bangka and Aton—is under evaluation, with further drilling planned for all three discoveries.
Unocal has drilled 12 deepwater wells in the Kutei Basin since June. Those 12 wells were drilled for an average cost of $4.6 million, with an average drilling time of 14.2 days. (Details of the individual well results are shown in the attached table.)
The Nakula #1 well was the first Unocal well drilled in water more than one-mile deep. Earlier, the company said that it was capable of extending the limits of the Sedco 601 semisubmersible drilling rig to water depths of up to 6,000 ft.
Looking forward, Unocal plans to proceed with its Indonesia deepwater exploration program on two fronts. In addition to the current well on the Bangka prospect, additional wells are planned for the Janaka North and Nakula prospects before the end of the year. In January, two to four Middle Miocene tests will be drilled on large anticlines in the Ganal PSC, south of the Makassar productive trend.
Unocal, through various subsidiaries, is operator of the East Kalimantan, Ganal, Sesulu, Rapak, and Makassar Strait PSC areas. The company holds working interests of 100% in East Kalimantan, 80% in Ganal and Sesulu (Lasmo 20%), 60% in Rapak (Mobil 30%; Lasmo 10%), and 50% in Makassar Strait (Mobil 50%). Under the terms of the PSCs, Unocal Indonesia and its affiliates, as contractors to Pertamina, the Indonesia national oil company, are entitled to varying shares of the oil and gas produced from commercial discoveries.
