An Integrated Geological and Geophysical Interpretation of the San Carlos Basin, Costa Rica

Abstract

Hydrocarbon exploration began in Costa Rica with Sinclair Corporation’s five well program of 1916–1923. Since then geological, geochemical, potential field, land, and marine seismic surveys have been made with 49 stratigraphic and exploration wells drilled, the majority of these in the Limon Sur basin. Some intriguing non-commercial oil and gas shows were encountered.

The San Carlos basin in northern Costa Rica was considered prospective and made an objective of the 1986–1989 RECOPEPCIAC exploration/technical assistance program. Building on sparse geological information and new potential field interpretations, 600 km of dynamite, multifold reflection and 50+ km of refraction seismic surveys were conducted there. These data were interpreted, along with older information, and drill hole locations were selected. These stratigraphic wells at Pataste No. 1 and Tonjibe No. 1 (Figure 1) were finished in November, 1987, and January, 1988, respectively. They significantly increased the understanding of the basin.