Raúl Giraudo¹, Hugo Belotti²
(1) Andina S.A, Santa Cruz de la Sierra, Bolivia
(2) Perez Companc S.A. S.A, Neuquen, Argentina

Abstract: Reducing exploration risk in a new and growing regional energy market in South America

The sub-Andean fold-and-thrust belt of northern Argentina and south central Bolivia is one of the most prolific gas provinces in South America. More than 24 tcf of gas and 600 million barrels of condensate and light oil were discovered in the last decades, and a similar amount might be yet to be found.

Thin-skinned deformation formed a generally in-sequence eastward-verging tectonic wedge. Shortening was transmitted to the foreland at the base of the Silurian Kirusillas Formation, and was partially accommodated as double-triangle zones with blind thrusts located at the base and top of the Devonian Los Monos shales. As a result, an important tectonic thickening was developed within the Los Monos formation and the overlying Carboniferous and Tertiary units were deformed passively.

The fractured Devonian Huamampampa and Santa Rosa formations are the most important targets for hydrocarbon exploration in the region. However, the complex deformation resulted in outcropping anticlinal axes being offset from their subsurface culminations.

The sub-Andean ranges have a rough topography and steep dips that impede good seismic data recovery. Many exploration wells failed because of lack of a successful structural interpretation.

New markets demanding for gas and gas-generated electricity are presently being incorporated in the southern cone of South America (Brazil, Argentina, Bolivia, Uruguay and Chile).

A major challenge consists of improving the structural model to reduce exploration risk in this complex and high-cost play.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana