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The Gibraltar Case Study, Northern Llanos Foothills, Colombia. Success Of A Complex Technical Business In Complicated EnvironmentsNormal access

Authors: T. Villamil, J. Muñoz, J. Sanchez, J.J. Aristizabal, J. Velasco, A. Fajardo, P.E. Luna, A. Mantilla, L.E. Peña, M.G. Paz, O. Silva, E. Sanchez, N.S. Meza, J. Martinez, L.A. Pachon and E. Gallardo
Event name: 8th Simposio Bolivariano - Exploracion Petrolera en las Cuencas Subandinas
Session: Oil and Gas Fields in the Subandean Basins
Publication date: 21 September 2003
Organisations: ACGGP
Language: English
Info: Extended abstract, PDF ( 2.01Mb )
Price: € 20

The Gibraltar discovery by Ecopetrol opened a frontier area of significant extent in the previously untested northern Llanos foothills province of the Eastern Cordillera of Colombia. The Gibraltar project when Ecopetrol captured the block had three main objectives and all were accomplished. The first objective was to verify or refute a structural geological model with a sidetrack that would reach the Paleocene Barco Formation and demonstrate the presence of hydrocarbons in the area. Ecopetrol´s hypothesis postulated that the well drilled originally by Occidental penetrated the backlimb of a single stack within a duplex structure in the central region of a triangle zone. This model was proven right after drilling three sidetracks. The Barco tested water with very low percentage of light hydrocarbons. The second purpose was to test presence and quality of hydrocarbons in the Mirador Formation. The original hypothesis was postulated based on a reinterpretation of unconventional petrophysics and unconventional fluids, this hypothesis argued for a missed or bypassed pay case. Tests of the Mirador Formation verified the presence of 57-degree condensate that flowed at a rate of 600 barrels per day and 44 million cubic feet of gas per day, flux restricted by gas separation and storage capacity. The third objective of Gibraltar re-entry was to find commercial hydrocarbons, open a new play, and to increase risk investment in the region. This third objective has not been verified yet but the following characteristics indicate that it is extremely likely that this is the case: the well is 2 km from a main pipeline with capacity, the hydrocarbons are of very good quality; the crest of the structure is at 6,500 feet, the shallowest discovery of the foothills; permeability from tests is of 800 m.d. being the highest of the foothills; finding cost for Ecopetrol was of 7 cents per barrel; finally and most importantly, the discovery was the first in the region.

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