Geology and Petroleum Potential of Saba Bank Area, Northeastern Caribbean: ABSTRACT

Abstract

Recent exploratory activity on Saba Bank in the northeastern Caribbean has provided geologic information showing that this frontier area possesses all of the attributes necessary for the commercial accumulation of hydrocarbons. The first well drilled in the area penetrated 9,370 ft (2,856 m) of sediments including 3,021 ft (921 m) of Eocene carbonates containing zones of good to excellent porosity. Geochemical studies show the presence of good but immature source rocks with the extractable hydrocarbons being migrated rather than indigenous. The geothermal gradient and vitrinite reflectance data indicated the threshold of the oil window would be reached around 10,000 ft (3,048 m). The second well was drilled to test a postulated reef on a basement high at a sufficient dept to fall within the oil window. The well bottomed in Eocene andesite at 13,881 ft (4,231 m). Reef carbonate was not encountered; the well penetrated turbidite sandstones and siltstones with low to moderate porosity and permeability. A test of gas shows recovered small amounts of C1-C5, but the formation is believed to have been badly damaged by severe mud loss during drilling. Geochemical studies confirm the presence of good source rocks. Reworked unmetamorphosed organic matter of probable early Eocene to Cretaceous age suggests that the Cretaceous cannot be considered economic basement in this area. Reinterpretation of the seismic data explains why the two wells were dry and indicates the presence of a submarine fan area, reefs within the oil window, and large structures in an area of t ick sediments of probable Cretaceous age. End_of_Article - Last_Page 249------------