ABSTRACT

Analysis of the tectonic evolution, structure, stratigraphy, depositional environments, facies changes, and habitat of proved hydrocarbons in the Gulf of Mexico-Caribbean region leads to the conclusion that numerous areas remain to be explored, some in supposedly well-explored trends. Some "explored" areas are still potential future hydrocarbon provinces because of hitherto uncritical acceptance of long-standing, but not necessarily correct, assumptions regarding the geology of the area involved. Lack of exploration of other areas can be attributed to: (1) limitations in drilling technology; (2) unfavorable economic factors; (3) restrictive legislation; (4) failure to develop new exploration techniques; and (5) failure to use properly some existing exploration techniques.

The Gulf of Mexico area essentially is tectonically stable, being underlain by oceanic crust and ringed by continental masses on which Precambrian and Paleozoic orogenic belts, post-orogenic deposits, and platform facies have formed. Subsequently, a major Mesozoic-Cenozoic fold belt formed in the Northern Central American orogen on the south and in the Mexican orthogeosyncline on the west. The Mesozoic-Cenozoic Gulf Coast geosyncline formed in the northwest and north. Thick platform deposits--mainly carbonates and evaporites-- deposited on the east.

The Caribbean oceanic plate is surrounded almost completely by orogenic belts. The Jurassic-Quaternary Southern Central American orogen developed on the southwest; the Jurassic-Quaternary Greater Antilles orthogeosyncline formed on the north and northwest; and the Jurassic-Quaternary Caribbean and Northern Andean orthogeosynclines formed on the south. North of Cuba and Haiti in the northwestern part of the Greater Antilles orthogeosyncline is the Bahama platform. Southwest and south of Cuba are the Yucatan platform and Northern Central American orogen. South of the Caribbean orthogeosyncline is nuclear South America. An Eocene-Recent island arc, including an active volcanic belt, closes the Caribbean on the east, and a late Tertiary-Quaternary belt developed in Central America and southern Mexico on the west. Local Cenozoic basins developed on almost all land areas within this complex region.

Future possible hydrocarbon provinces include: (1) offshore Cretaceous reef and forereef extensions of the Golden Lane, eastern Mexico; (2) additional Panuco-Ebano-type fields in Late Jurassic-middle Cretaceous basinal carbonate facies of eastern Mexico; (3) additional Poza Rica-type fields in intertonguing zones between Late Jurassic-middle Cretaceous reef carbonates and basinal carbonate facies of eastern Mexico; (4) Parras and similar types of basins, associated with structural and stratigraphic traps, in the Late Jurassic-Tertiary sequence of eastern Mexico; (5) new pay zones in the Rio Grande embayment; (6) Cretaceous reef buildups and other types of stratigraphic traps around the San Marcos arch, Sabine uplift and Wiggins arch, as well as in the areas between the arches and uplifts named, and extending offshore in the West Florida shelf area; (7) pre-Monroe "gas rock" plays in the Cretaceous, Jurassic, and Palezoic of northeastern Louisiana, southeastern Arkansas, and northwestern Mississippi, and Paleozoic plays from North Louisiana to South Texas; (8) pre-Werner or pre-Louann Salt objectives along the interior part of the Gulf coastal plain; (9) Jurassic-Cretaceous-early Tertiary reefs and sandstone trends in the Florida parishes of Louisiana; additional Paleocene-Eocene-Poth Sand-type plays in the downdip marine Wilcox of the Texas and southern Louisiana; (11) deep sandstone trends in the post-Wilcox of the Gulf Coast geosyncline, both offshore and onshore; (12) deep-water drilling to both shallow and deep objectives beneath the outer continental shelf and the upper continental slope; (13) Cretaceous and Jurassic of Mississippi-Alabama-northern Florida; (14) offshore Jurassic, Cretaceous, and Tertiary reefing on the West Florida shelf; (15) Bahamas platform; (16) Mesozoic-Tertiary carbonates along the north coast of Cuba; (17) Late Cretaceous and/or Tertiary marine basins in Cuba, Jamaica, Hispaniola, Puerto Rico, Barbados, and Trinidad; (18) offshore plays east and south of Trinidad; (19) Orinoco delta, both onshore and offshore; (20) Gulf of Paria; (21) Cretaceous-early Tertiary objectives in the Barinas basin of southwestern Venezuela; (22) additional possibilities in Cretaceous and Tertiary trends in the Eastern Venezuela basin and Maracaibo basin, as well as in the Gulf of Venezuela; (23) Tertiary basins of the Southern Central American orogen; (24) Nicaragua Rise from Nicaragua-Honduras to Jamaica; (25) Tabasco (Mexico)-Peten (Guatemala) fold belt of the Northern Central American orogen; (26) offshore and onshore British Honduras, including Sarstun embayment; (27) Yucatan Peninsula and Campeche bank; and, ultimately, (28) the Sigsbee diapirs, central Gulf of Mexico.

Not all of these areas listed can be considered to have equal potential. Considering only those areas where 20 or less exploratory tests have been drilled, more than 250,000 sq mi, an area the size of Texas, is relatively unexplored. Including areas where exploratory drilling ranges from 21 wells to extensive drilling, more than 500,000 additional sq mi has not been explored completely. This total of 750,000 sq mi remains to be tested carefully before pessimistic attitudes are justified.

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