Print this pagePetroleum Potential of Oil Basins of Colombia, South America
Nicolas Beltran, Roberto A. Leigh
Commercial oil production in Colombia dates back to 1918. The country's cumulative production to December 1988 is estimated at 3.0 billion bbl. Even though current oil production averages 400,000 bbl of oil/day, a level of 600,000 bbl of oil/day is expected from 1991 to 2000.
Colombia's production comes mainly from the Llanos, Putumayo, Magdalena, and Catatumbo basins, which have an aggregate area of 269,000 km2. During the past five years, exploratory drilling in the Llanos and Upper Magdalena basins has contributed to a substantial increase in reserves. Since the 1983 discovery of the giant Cano Limon field by Occidental, the Llanos basin has become the main producing area of the country and the host to the largest remaining reserves. The Magdalena basin leads in cumulative production with 2.0 billion bbl.
The producing basins are genetically related as they are the remnants of a Cretaceous miogeosyncline that extended along western South America from Venezuela to northern Argentina. The present-day structural configuration of these basins is the result of the Andean orogeny. Miocene uplift of the axial portion of the Cretaceous miogeosyncline gave rise to the Eastern Cordillera of Colombia, causing the separation of these basins. The productive reservoirs are Cretaceous and lower Tertiary shallow marine and continental sandstones. Organic-rich, mature Cretaceous-early Tertiary shales sourced the reservoirs.
Since 1918, 560 wildcats have led to the discovery of 100 oil and gas fields in these basins. The wildcat ratio averages one well/200 km2 except in the Llanos basin, where the wildcat density is one well/1,800 km2, comparable to the stage of exploration of western Canada in 1950. According to official sources, it is estimated that in addition to the 2 billion bbl of proven reserves, there are 10 billion bbl of potential reserves to be discovered in these basins.
AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.