Northern South America
This paper synthesizes technical, commercial, and strategic issues regarding the petroleum systems and exploration of the northwest corner of South America in three parts: a technical analysis of the presence and distribution of the hydrocarbon systems; analysis of the areas with the largest remaining potential; and Colombia’s exploration strategy in relation to its geology and potential.
The technical portion outlines, with the use of countrywide paleogeographic maps, the main reasons for the presence and distribution of hydrocarbons in the region. Regional petroleum systems are described using a process and genesis methodology. The proposed hypothesis for source-rock quality and distribution combines regional plate tectonics with the formation of a large igneous province, global warming, increased upwelling, widespread anoxia-dysoxia, and sea-level rise. The hypothesis for reservoir distribution and quality comprises details of a regional orogenic event that affected the northwest margin of South America. The distribution of different reservoir qualities is determined by the erosion of an elongated mountain belt formed by this orogeny, the associated synorogenic sedimentation, and the evolution of a closing foreland basin that received sediments from the west from a mountain chain with varied basement stratigraphy, and from the east, sediments from the Guyana Shield. The explanation for regional seal deposition lies in the tectonic extension and foundering of large portions of Colombia and western Venezuela, the regional subsidence associated with diminished plate-tectonic convergence, and the associated increase of accommodation space. The inversion of the Eastern Cordillera and the development of doubly verging thrust belts bounding the mountain belt explain the formation of most traps. Adjacent forelands and foredeeps to the mountain belt and thick molasse packages combined with tectonic burial of the source rock explain generation and migration patterns. This paper also considers where the largest volumes of hydrocarbons will be found in the future, based on technical issues, and on the exploration history of different play areas in Colombia.
Figures & Tables
The Circum-Gulf of Mexico and the Caribbean: Hydrocarbon Habitats, Basin Formation and Plate Tectonics
The Circum-Gulf of Mexico and the Caribbean has long been one of the world's most important petroleum provinces, as well as one of the world's most geologically complex regions. These two characteristics have resulted in an extensive amount of ongoing research by both industry and academia. AAPG Memoir 79, The Circum-Gulf of Mexico and the Caribbean, is the first volume in more than a decade to document such a wide range of research on the geology of this vast area. Of the total 44 papers, roughly two-thirds pertain to the Gulf of Mexico, with an emphasis on the Mexican portion of the basin, and to the petroliferous areas of the southern Caribbean, including Colombia, Venezuela, Cuba, and Trinidad and Tobago. The remaining papers relate to the Antilles and Central America, as well as a series of papers that address region-wide topics such as plate tectonic evolution. A significant number of papers were contributed by authors from national oil companies and universities from within the region.