Stratigraphy and structure of regionally-isolated hydrocarbon occurrences in the Azua Basin, south-central Dominican Republic (Northeastern Caribbean)

Abstract

AbstractOil seeps and small-production oilfields in south-central Hispaniola are regionally isolated from much larger hydrocarbon provinces in the circum-Gulf of Mexico and northern South America. In this study, we evaluate the tectonic, stratigraphic and structural setting of these hydrocarbon occurrences. The zone of late Miocene to Recent oblique convergence includes the Bahamas Platform, Cretaceous and Paleogene arc rocks in Hispaniola, and the Cretaceous Caribbean oceanic plateau. Twentieth-century hydrocarbon exploration in Hispaniola has been concentrated on the elongate, NW- to WNW-trending, thrust- and strike-slip fault-bounded Cibao, San Juan–Azua and Enriquillo basins. Analyses of Cretaceous to Neogene rocks in the Dominican Republic have revealed that most rocks contain poor to marginal total organic carbon values. In the Azua Basin, a shallow marine, basin-edge facies of the middle Miocene Sombrerito Formation underlies the area of natural oil seeps and limited historical oil production and exhibits good to excellent total organic carbon values greater than 1%. Structural traps for oil at the Maleno and Higuerito oilfields of the Dominican Republic are large anticlines formed in post-late Miocene time. Reservoir rock for oil at the Maleno and Higuerito oilfields of the Dominican Republic is submarine fan-deposited sandstone of the late Miocene Trinchera Formation.