Cusiana field in Colombia holds estimated recoverable reserves of as much as 1.5 billion bbl of crude oil and condensate and "additional large volumes" of gas, a unit of British Petroleum Co. plc disclosed last week.
However, the full extent of reserves won't be known until more wells are drilled and field limits firmly established, BP said.
BP Exploration Co. (Colombia) Ltd. and partners Total Exploratie en Produktie Mij. BY and Triton Colombia also have found a second field with their 1 Cupiagua wildcat, 15 km north and on the same license block, with reserves about one-third as large those of Cusiana (see map, OGJ, Oct. 26, p. 25).
Cusiana and Cupiagua are on a geological trend BP believes extends north into the separate 5,000 sq km Piedemonte license area, owned 100% by BP, where it is drilling the 2 Pauto wildcat.
CUSIANA ACTION
BP bases its Cusiana reserves estimate on data from three completed wells and six appraisal wells at or near target depth. One of the completed wells, 1 Buenos Aires, is flowing about 10,000 b/d on a long term production test.
Three of the appraisal wells - 3 Cusiana, 4 Cusiana, and 3 Buenos Aires - have drilled into pay zones. BP expects the other three - 2 Buenos Aires, 5 Cusiana, and Rio Chitamena - to reach the reservoir within the next 6 weeks.
Plans to develop Cusiana and upgrade export pipelines are being drawn up by the working interest partners and state owned Empresa Colombiana de Petroleos (Ecopetrol), which has an option to acquire a 50% interest. Production could amount to as much as 150,000 b/d of oil by the end of 1995, BP said.
BP will book 225 million bbl of reserves at yearend 1992 to reflect its 15.2% net share in Cusiana after Ecopetrol's exercise of its option. BP's share of Cupiagua reserves are to be booked at the end of 1993 when appraisal drilling is complete.
A preliminary evaluation of Cusiana indicates a development cost per barrel that compares favorably with costs for similar major onshore oil provinces elsewhere in the world, BP said.
The preliminary Cupiagua reserves estimate is based on results of 1 Cupiagua, which has reached the pay zone at about 12,400 ft after 7 months of operation and is drilling the reservoir section.
BP plans four Cupiagua appraisal wells in 1993.
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