Bolivian Petroleum Systems: Paradigm Shifts

Abstract

The petroleum systems of the Bolivian basins have been revised under the light of a fully integrated regional study. The stratigraphic review, including biostratigraphy, sedimentological core description and seismo-stratigraphic investigations led to new consistent tectono-sedimentary models and allowed the identification of several conceptual plays. The geochemical synthesis coupled with the stratigraphic study allowed a better definition of the potential source rocks. The thermal calibration of the temperature and maturity data is only possible by taking into account an increase of the heat flow during Triassic-Jurassic times. Two main phases of hydrocarbon expulsion are calculated. The first began in Triassic-Jurassic time and the second was contemporaneous with Andean deformation and associated foreland basin. During the Andean phase, the hydrocarbon charge of the sub Andean traps was controlled by expulsion in the synclines and in the anticlines. Mechanical expulsion related to burial is the main expulsion mechanism in the synclines sometime associated with increase of maturity. In the case of anticlines, expulsion occurred due to the hydrocarbons’ volume expansion during uplift.

AAPG Datapages/Search and Discovery Article #90326 © 2018 AAPG Latin America & Caribbean Region, Optimizing Exploration and Development in Thrust Belts and Foreland Basins. Santa Cruz de la Sierra, Bolivia, June 6-8, 2018