A group of companies delineating Colombia's Cusiana field has accelerated drilling there with plans to establish commerciality by mid-1993.
Activities include substantial appraisal work to determine Cusiana's areal extent, reserves, and well productivity.
Tests of 1 Cusiana wildcat well and 2A Cusiana and 1 Buenos Aires stepouts indicate the field could rank among the Western Hemisphere's largest oil and gas discoveries. Early, unofficial estimates of potential field reserves have been 1-10 billion bbl of oil.
Cusiana partners are operator BP Exploration Co. (Colombia) Ltd. and Total Exploratie en Produktie Mij. BV-each with 38% interest-and Triton Colombia, a subsidiary of Triton Energy Corp., Dallas, with 24%. Those interests will be halved when the project is deemed commercial and Colombia's state petroleum company Empresa Colombiana de Petroleos exercises an option to take a 50% interest.
Triton has reported the status of Cusiana development in its annual report for fiscal 1992 ended May 31, which was published earlier this month.
CURRENT ACTIVITY
At the annual report's presstime, Triton reported six wells drilling ahead in the field, including I Cupiagua exploratory well on 92,455 acre Santiago de las Atalayas association contract area about 14 km north of 1 Cusiana.
Partners also are drilling five appraisal wells, three on Santiago contract area and two on the adjacent 38,894 acre Tauramena association contract area.
Portions of Cusiana field overlap both contract areas. When completed, the six wells in progress will increase to nine the number of wells drilled on the two tracts by the group. Partners have budgeted 18-22 wells through fiscal 1994.
Operator BP expects Cusiana wells each to produce 10,000-15,000 b/d of oil. Initial field production is expected to begin in second half 1993 at 40,000 b/d. Cusiana partners have decided to reinject produced Cusiana gas as part of a gas lift program.
Plans call for using an existing pipeline to transport production from the field until installation of a new line is complete.
Once Cusiana commerciality is established, partners will have the right to produce oil and gas from Santiago contract area through 2010 and from Tauramena through 2016.
CUSIANA DISCOVERY
Triton said Cusiana's discovery well-1 Cusiana wildcat on Santiago contract area-in December 1988 encountered a 1,300 ft gross hydrocarbon column in Oligocene Carobonera and Eocene Mirador sands, but didn't penetrate the highly prospective Paleocene Barco and Cretaceous Guadalupe formations.
Despite hole damage, 1 Cusiana flowed 1,930 b/d of liquids and 13.4 MMcfd of gas.
Cusiana partners on July 9, 1991, announced that 2A Cusiana delineation well-drilled to a total depth of 15,060 ft-cut two pay zones that tested a combined 6,780 b/d of oil and 22.1 MMcfd of gas through 1/2 in. chokes (OGJ, July 15, 1991, p. 25). The well logged a 1,900 ft gross hydrocarbon column.
Two Guadalupe intervals in 2A Cusiana at 14,100-14,600 ft flowed 2,800 b/d of 30-37 gravity oil and 3.3 MMcfd of natural gas with 1,550 psi stabilized wellhead pressure and 2,240 b/d of 30-37 gravity oil and 7.3 MMcfd of gas with 2,300 psi stabilized wellhead pressure. Barco intervals at 13,870-14,070 ft flowed 1,740 b/d of 38 gravity oil and 11.5 MMcfd of gas with 2,940 psi stabilized wellhead pressure. Two Mirador intervals below 13,160 ft-where testing was completed at a later date-flowed a combined 1,878 b/d of 40-44 gravity oil and 13.5 MMcfd of gas through a 1/2 in. choke with 1,800 psi flowing tubing pressure.
1 BUENOS AIRES TESTS
Earlier this year, Cusiana partners 1 Buenos Aires delineation well-in Tauramena contract area about 9 km south of 1 Cusiana-flowed 1,539 b/d of 25-27 gravity oil and 1.4 MMcfd of gas through a 1/2 in. choke with 1,350 psi flowing tubing pressure from a Barco interval at 15,030-045 ft (OGJ, Jan. 20, p.68).
In later tests, the well flowed 5,460 b/d of 33-41 gravity oil and 14.6 MMcfd of gas through a 1/2 in. choke with flowing tubing pressure of 1,350-1,950 psi from three Mirador formation intervals at 14,220-14,580 ft.
Cusiana's 1 Buenos Aires well is undergoing long term production tests at rates subject to available pipeline capacity, about 10,000 b/d of oil. The well has production tubing capacity for as much as 16,000 b/d of oil.
In addition, partners are monitoring reservoir characteristics in 2A Cusiana and 1 Buenos Aires.
Copyright 1992 Oil & Gas Journal. All Rights Reserved.
