Hábitat De Hidrocarburos En El Pie De La Sierra De La Faja Corrida Subandina, Cuenca De Tarija. Area De Santa Cruz, Bolivia

Three previously unproductive reservoirs in the region lying between the Parapetí River and the Santa Cruz de la Sierra city, have recently been successfully tested by Pluspetrol S.A. The tectonic setting of these gas discoveries is the Foothills of the Subandean Thrustbelt of the Tarija Basin. The Tajibos success is a four-way closure anticline linked to the Emergent Thrust Front where the gas is lodged in the lowermost Tertiary Petaca fluvial sandstones. The Tacobo gentle ramp related anticline, produced outstanding gas rates from Lower Devonian Huamampampa fractured quartzite sandstones. The latter trend bears a notable amplitude anomaly but in a different structural level. There, the Curiche well tested gas from Tertiary Chaco fluvial ephemeral sandstones. The Río Seco structure is a fault propagation fold with a gas accumulation in the Upper Carboniferous Escarpment peri-glacial fluvial sandstones, discovered by YPFB in past decades. Non-commercial gas was tested here from Mid Devonian Iquiri shelf stormy sandstones. The gases form a group that has similar characteristics with minor differences that have been interpreted to be generated by the same source rock section, according to geochemistry evaluation and gas isotope data. Faults are considered to be the main migration pathway, since the hydrocarbons are trapped in different reservoirs and structural levels. During the last four years, the use of technology and 3D seismic as key elements of an important exploratory effort, led to the discovery of these gas accumulations that amount almost 1 TCFG recoverable reserves.