David Knott
International Editor
Development of Colombia's Cusiana and Cupiagua oil fields by BP Exploration Co. (Colombia) Ltd. depends strongly on export pipeline capacity.
There is limited pipeline capacity short term. So the fields will be developed in two phases.
About 10,000 b/d is produced on long term test at present. Oil moves through an Empresa Colombiana de Petroleos (Ecopetrol) 12 in. pipeline running from Araguanay to the Covenas terminal on the Caribbean Sea coast.
Production will stay at this volume until mid-1994.
BP plans to apply this month to declare Cusiana field commercial (OGJ, Apr. 26, Newsletter). Approval could launch a development program that may see production reach 800,000 b/d by 2000.
The Cusiana acreage is one of several blocks BP holds in the Northeast Colombia (see map, OGJ, Jan. 20, 1992, p. 68).
Cusiana field lies near a 40,000 b/d Ecopetrol pipeline from Araguanay, which meets the 75,000 b/d Central Llanos pipeline at El Porvenir. This in turn joins the 150,000 b/d Oleoducto de Colombia (ODC) pipeline at Vasconia and continues northwest to Covenas.
To step up Cusiana oil flow production to 150,000 b/d by the end of 1995, as Phase 1 of development, BP plans to lay a 20 in. line from Cusiana to El Porvenir and a 30 in. loop to upgrade the Central Llanos section of the ODC pipeline to 220,000 b/d. First phase pipeline costs are estimated at $300 million.
Beyond 1995, BP is considering three options: laying a new pipeline, further upgrading of the Araguanay-El Porvenir-Covenas route, or tying into Occidental Petroleum Corp.'s 230,000 b/d Cano Limon-Covenas pipeline, which passes north of Cusiana. Pipelines for Phase 2 development will cost more than $1 billion gross, BP said.
PRODUCTION
Before Cusiana's discovery, Colombia had reserves of less than 2 billion bbl of oil and 3.5 tcf of gas. Colombia's current production is about 450,000 b/d, with 200,000 b/d of exports shipped out of the Covenas terminal. Gas flow is 400 MMcfd.
BP estimated Cusiana oil reserves at 1.5 billion bbl and Cupiagua at 500 million bbl and is not putting a figure on gas reserves because gas is recycled to aid oil production.
Juan Maria Rendon, president of Ecopetrol, said Cusiana and Cupiagua field reserves will at least double oil and gas reserves for Colombia. Although Cusiana gas has not been booked as reserves, a BP official confirmed Rendon's estimate of at least 3.5 tcf gas reserves in Cusiana.
Cusiana's gas reserves were enough to trigger Ecopetrol interest in developing a national gas pipeline network. Rendon said Colombia's gas reserves may reach 8 bcf when Cusiana, Cupiagua, and Piedemonte field delineation is complete.
In Cusiana field the 1 Buenos Aires well has been on long term test since September 1991, producing 10,000 b/d of oil that is sent via a 7 km pipeline to facilities at the 2A Cusiana wellsite.
The 2A Cusiana is undergoing gas injection tests. About 20 MMcfd of gas will be sold to Ecopetrol starting in 1994. A pipeline is being built from Cusiana field to Apiay, where an electrical power generation plant will be converted to gas fuel, requiring 10 MMcfd. The rest will move by pipeline to Bogota for local use.
In mid-1994 two 40,000 b/d oil production units will be installed on a site near the 2 Buenos Aires well pad, with a third to be installed, if required, in third quarter 1995.
Production will jump to 50,000 b/d in mid-1994, rising to 130,000 b/d in 1995 and 150,000 b/d by yearend. BP has not decided Phase 2 production rates, although Ecopetrol said this could be 600,000-800,000 b/d of oil. Development of Cusiana and Cupiagua has cost $2/bbl gross to date, BP said.
RESERVOIRS
Cusiana and Cupiagua fields are believed to have been fed their oil from Cretaceous Gacheta source rocks on a trend that runs from Venezuela through Colombia into Ecuador. The fields hold three reservoirs Eocene Mirador and Barco and the Guadalupe. The Mirador can produce 15,000-20,000 b/d/well.
Tony Hayward, BP Colombia exploration manager, said Cusiana field's formations were first identified in 1971, long before BP acquired the acreage. In 1973 Ecopetrol drilled the 1 Tauramena discovery well, followed in 1976 by its 2X Tauramena appraisal.
"These wells found gas/condensate in the Mirador," Hayward said. "They were subsequently declared uncommercial, and the acreage was opened to the industry."
About 15 companies held the acreage until Triton Colombia Inc. acquired it in 1982. BP took a farmout on the block in 1986 and began drilling its 1 Cusiana in 1987. The well flowed 6 MMcfd and 600 b/d of condensate from the Mirador.
BP then spudded 2 Cusiana in 1988 but ran into mechanical problems. A sidetrack hole, 2A Cusiana which got under way in 1989, cut a gross 1,500 ft oil column (OGJ, Oct. 26, 1992, p. 24).
CUSIANA APPRAISAL
Last year BP completed appraisal of the western extent of Cusiana field and announced an early estimate of reserves (OGJ, Nov. 2, 1992, p. 40).
All of last year's appraisal wells except 5 Cusiana logged hydrocarbons. The 3 Buenos Aires and 4 Cusiana are being sidetracked updip, to be completed as production wells. Seven rigs are operating in Cusiana and Cupiagua fields this year.
The successful wells will be completed for production as part of Phase 1 development so costs can be recovered from Ecopetrol. The 5 Cupiagua is suspended but will most likely be sidetracked updip and tied in.
Phil Mead, BP Colombia operations manager, said BP has been in top gear since mid-1991 to appraise Cusiana field to meet a May deadline for declaration of commerciality.
Early drilling was hampered by lack of wellbore stability and penetration rates as low as 2-3 ft/hr, resulting in wells taking more than 1 year to drill.
Drilling time has been reduced with experience. BP's 1 Los Cedros well, appraising the southwest portion of Cusiana field, reached 13,000 ft measured depth after 40 days. Target is the Mirador reservoir at about 17,000 ft. The well has a 40 sail angle from an 8,000 ft kickoff point.
CUPIAGUA APPRAISAL
The Cupiagua reservoir is a distinct structure north of Cusiana. The 1 Cupiagua well, on which field reserve estimate is based, is being tested.
Appraisal began in April with 2 Cupiagua, intended to test extensions of the field to the south and west. Testing of I Cupiagua is to be complete this month, when the rig will be moved to spud the 3 Cupiagua appraisal.
In 1994 a 3D seismic survey of Cupiagua is planned, which will be linked to long term tests of the reservoir. Results from the 1993 appraisal drilling program will help guide a study of Phase 2 production options.
Drilling of Cupiagua development wells is scheduled for 1995.
PIEDEMONTE EXPLORATION
BP suspended the 1 Tamara wildcat on the Piedemonte block as a tight hole early in 1992. The company has a 10% interest in the 1 Volcanera currently being drilled on adjacent acreage by operator Maxus Energy Corp.
Two BP wells will be spudded on the 2,000 sq km Piedemonte block this year. The first, 1 Tacare, is to be started early in July. A second, so far unnamed, will be drilled in the southwest part of the block later in the year.
A $50 million/year budget has been set for Piedemonte exploration, allowing for two wells/year to the end of 1995. Early Cusiana wells cost about $25 million to drill, but Hayward said improved knowledge has helped halve well costs.
CONTRACTS
BP operates the Santiago de las Atalayas, Tauramena, Piedemonte, Rio Chitamena, Upia, and Monterallo association contracts with a 38% share before Ecopetrol exercises its 50% share option and halves the BP interest. Similarly, Total Exploratie en Produktie Mij. BV has a 38% stake, while Triton holds 24%.
Cusiana and Cupiagua field developments programs are bound by association contracts between Ecopetrol and foreign partners that allow 6 years for exploration on a block, " years of production, and royalty payments of 20% of production.
Equity and costs are split 30-50 if Ecopetrol buys in as a field is declared commercial at the end of the 6 year exploration period. Ecopetrol then pays 50% of drilling and development costs on successful wells to date.
Piedemonte is governed by a similar contract, except that costs are split 50-50 between Ecopetrol and its foreign partners, while equity is decided on a sliding scale from 50-50 to 70% Ecopetrol and 30% for partners.
The 6 year exploration period for Cusiana expires this month--hence BP's application to declare the field commercial. Ecopetrol is scheduled to approve field commerciality within 60 days. The 22 year production clause means BP has until 2016 to deplete Cusiana reserves.
Copyright 1993 Oil & Gas Journal. All Rights Reserved.