Unocal Corp. has claimed three U.S. records for extended reach drilling in two horizontal wells it drilled off California.
Well A-21, drilled from Platform Irene in the Point Pedernales Unit 20 miles northwest of Point Conception, broke two records: longest horizontal reach, 14,671 ft, and longest pay zone section, 5,990 ft.
Well C-29, drilled from Platform C in Dos Cuadras field in the Santa Barbara Channel, broke the record for highest average angle, 76, from start to finish. It taps a producing zone that was not developed previously because of the reach limitations of conventional drilling.
Unocal said the drilling achievements were made possible by techniques it developed and patented. It has used extended reach technology elsewhere, including the Gulf of Mexico and the Dutch North Sea.
THE DETAILS
Well A-21 went to 16,714 ft measured depth and 5,032 ft true vertical depth, resulting in a 71.1 average angle. The well is producing 2,800 b/d of oil from Miocene Monterey.
It is the latest well in an extended reach drilling program from Platform Irene that has allowed development of 22 million bbl of oil reserves' Without extended reach technology, Unocal said, it would have been necessary to set a second platform to develop the reserves.
Well C-29 is one of four extended reach wells completed in Dos Cuadras field off Carpinteria. Wells C-29, C-48, C-49, and C-50 were drilled from Platform C with horizontal completions in the Pliocene Brown zone. The horizontal sections of these four wells average 1,724 ft. They produce a total of 1,200 b/d of oil. Six more extended reach wells are planned for this field next year.
Unocal operates the Point Pedernales Unit with a 23.95% interest. Its partners are units of Amoco Corp., Chevron Corp., Elf Aquitane, Exxon Corp., and Mobil Corp.
Unocal operates Dos Cuadras field with a 25% interest. Its partners there are units of Chevron, Mobil, and Texaco.
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