Abstract

The most important source rocks that generate hydrocarbons in the eastern Caribbean basins are Cenozoic in age. Geochemical analyses of rocks and oils from the Greater Antilles region, Barbados Accretionary Prism, Tobago Trough, Cariaco Basin, Urumaco Trough, Falcon Basin, and Guajira Basin prove the existence of Paleogene and Neogene source rocks that have generated hydrocarbons through time. Along the Greater Antilles region, the middle Miocene Sombrerito Formation contains immature oil-prone source rocks, whereas in the vicinity of the Virgin Islands, Eocene and Oligocene strata have gas potential. Oil fingerprinting of Azua-San Juan Basin oils suggests the existence of a Miocene to Pliocene carbonate source rock deposited in a possible lacustrine environment. The Eocene Joe’s River Formation and Scotland Group within the Barbados Accretionary Prism contain source rocks, which are oil-and gas-prone, respectively. These sequences could have generated the Barbados Island’s oils. In the southern part of the Tobago Trough, an immature middle Miocene section with fair to good Type III kerogen source rock has been identified. The Miocene, Oligocene, and Eocene sequences drilled in the Cariaco Basin contain source rock intervals, which could generate mainly gas and minor amount of oil. In the Falcon Basin, the Eocene and Miocene sequences have fair to good potential to generate gas and minor oil. The Miocene in the Guajira Basin contains a fair to good gas-generating source rock, and the large gas accumulations in the basin were generated mainly by microbial activity from this Miocene sequence.

The existence of Cretaceous oil-prone source rocks in the Caribbean region is quite uncertain because of limited well penetrations, poor outcrops, and discontinuous seismic coverage. Consequently, their aerial extent, thickness, and distribution of organic facies are very limited. To date, there are no evidences to document the presence of the Upper Cretaceous La Luna and its equivalents within the Caribbean plate.