--> ABSTRACT: Assessment of Coalbed Methane Resources in the Bogotá Basin, Colombia, by Mario García-González; #90906(2001)

Datapages, Inc.Print this page

Mario García-González1

(1) IER University of Wyoming - Universidad Industrial de Santander, Laramie, WY

ABSTRACT: Assessment of Coalbed Methane Resources in the Bogotá Basin, Colombia

The Bogota Basin is located at the axis of the Eastern Cordillera of Colombia, and covers an area of 3,200 km2. Coal beds within the basin are confined mainly to a series of parallel, northeast-trending synclines, which extend over 90 km.

The Guaduas Formation (Maestrichtian age) is the only coal-bearing unit in the basin, ranging in thickness from 800 to 1800 m, with a net coal thickness of 4-12 m. Nine Guaduas coalfields were evaluated for coalbed methane (CBM) potential: Subachoque, Rio Frio, Checua, Cogua, Tomine, Santa Rosa, Suesca, Tunja, and Sogamoso. The Checua, Sogamoso, and Tunja coalfields are the best Guaduas CBM prospects.

Guaduas Formation coals are of high to low, volatile bituminous rank; vitrinite reflectance values range from 0.5 to 1.6%, at depths ranging from the surface to 300 m. Mines in the Checua coal field are known to have high gas content, and gas seeps are widespread over this syncline. Gas content of the subsurface coals (determined by desorption) ranges form 30 to 500 scft/Ton coal; the lower values have resulted from early degasification of the mines. Petrographic and desorption studies indicate that as gas content increases, inertinite and vitrinite reflectance increase.

Guaduas Formation fractures have a regional azimuth of 129°, with a suborthogonal fracture pattern. Fracture intensity and, hence, permeability, are high for these CBM prospects.

The estimated CBM resource in Guaduas coals in the Bogota Basin is 10 Tcf; this resource has excellent market potential due to its proximity to the city of Bogota.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado