Petroleum Potential of Permian Carbonates in Northern South America

Laya, Juan Carlos¹; Tucker, Maurice E.; and Tucker, Maurice E.
¹[email protected]

In the last decade, Paleozoic rocks have been identified as potential future reserves oil and gas reserves in several countries around the world. The petroleum potential of the Upper Paleozoic strata in northern South America is noteworthy in view of the correlations with hydrocarbon-bearing strata and source rocks in neighboring Brazil, the southern USA and Peru-Bolivia areas, not only for conventional oil and gas reservoirs also, for unconventional shale targets.

In the northern part of South America, specifically in Venezuela and Colombia, the Upper Paleozoic stratigraphic record is poorly documented but the succession there reveals major changes in facies which can be related to the global-scale changes. Those changes have been recorded in the strata which have been described in detailed fieldwork in the Venezuelan Andes supported by petrographic studies and geochemical data. This data set was used for interpretation the potential petroleum systems in this area, also, the published data available.

Sedimentation occurred on an extensive ramp which probably dipped basinward towards the north, towards the open ocean within the foreland basin which has been named Muchuchachi basin. The Permian rocks in the MB can be followed through Colombia to the west and southwest, where a few successions of limestone and shale with fusulinids occur. The MB may well have been connected to the basins in Perú and Bolivia to the south, and with those in the north in the Mexican and Guatemala areas which have suffered similar depositional processes.

Finally the elements of the petroleum system for the Permian rocks have been considered for the strata and as a result, it can be proposed that, firstly, fractures in finer-grained facies have the potential to provide reservoir rocks, and secondly, The values of TOC varies between 0.28 to 1.48 % that are acceptable as a potential source rock. However, the values Tmax have been obtained from rock-eval analysis are in a range between 518°C to 353°C with an average of 490°C there are considerable high but still can consider and there could have been a gas generation window through the basin. The high content of finer-grained facies with low permeability provides the Permian rocks a high potential to perform as a seal, as well as possibility to develop stratigraphic traps. In addition, few authors have been pointed out potential structural traps in Barinas-Apure basin and could be extended to Los Llanos basin in Colombia.

AAPG Search and Discovery Article #90166©2013 AAPG International Conference & Exhibition, Cartagena, Colombia, 8-11 September 2013