Exploration for Cretaceous Deep-water Reservoirs in the Circum-Caribbean Region: Historical Review and Expectations for the Future
Robert N. (Bob) Erlich
Vice President, Exploration and New Ventures, PanAtlantic Exploration Company
Historical exploration efforts within the Circum-Caribbean region have not typically targeted Cretaceous reservoirs for a variety of technical and commercial reasons. The principal exceptions to this have been exploration efforts along the north coast of Cuba during the 1950's (sporadic since then), some wells on- and offshore Honduras and Nicaragua during the 1930's-1970's (three recent wells in the 2000's), and five wells in the Bahamas during the same time period. Renewed interest in Cretaceous reservoirs began in earnest during the mid-late 1980's, mainly as a byproduct of successful exploration in Eastern Venezuela's Furrial Trend, though these discoveries are concentrated principally within Neogene-Paleogene strata.
Exploration for Cretaceous targets has focused almost exclusively on Trinidad since this time, and results have not been overwhelmingly positive, regardless of whether the objectives were located onshore or offshore. Further interest in the Cretaceous has been generated recently by the discovery of commercial accumulations in slope and basin floor fan/channel complexes, most commonly found along the Equatorial Atlantic margins of West Africa and South America (the "Transform Margin Play"). Despite these recent successes, Cretaceous reservoirs and traps continue to yield unpredictable drilling results, especially along the margins of northern South America.
Significant technical risks include reservoir presence and deliverability, hydrocarbon charge access, and trap/seal integrity. Commercial challenges include hydrocarbon type (gas vs oil), volumes required for commercial development, development costs (hub and spoke versus stand-alone accumulations; number of development wells and FPSO's needed), and decreasing contractor take. A quick review shows that nearly all successful (?) wells in the trend have been drilled from 5-40 km down depositional dip from the Cretaceous paleo-shelf margin, though the technical factors mentioned above do not guarantee this "sweet spot" will hold up over the long term. While new discoveries in deep-water Cretaceous reservoirs are possible within the Caribbean-northern South America region, significant technical and commercial risks will continue to impact new exploration drilling.
AAPG Search and Discovery Article #90203 © AAPG Geoscience Technology Workshop, Trinidad and Tobago Deep Horizon and Deep Water Frontier Exploration in Latin America and the Caribbean, March 9-11, 2014, Port of Spain, Trinidad