Geology topics

Research about U.S. Gulf Coast

Source-linked reports with geographic coverage including U.S. Gulf Coast.

2 recordsLinked to original sources

USGS2013

Geologic model for the assessment of undiscovered hydrocarbons in Lower to Upper Cretaceous carbonate rocks of the Fredericksburg and Washita groups, U.S. Gulf Coast Region

As part of the assessment of undiscovered oil and gas resources in Jurassic and Cretaceous strata of the U.S. Gulf Coast in 2010, the U.S. Geological Survey assessed carbonate rocks of the Fredericksburg and Washita groups and their equivalent units underlying onshore lands and State waters. One conventional assessment unit extending from south Texas to the Florida panhandle was defined: the Fredericksburg-Buda Carbonate Platform-Reef Gas and Oil assessment unit. Assessed strata range in age from Early Cretaceous Albian to Late Cretaceous Cenomanian. The assessment was based on a geologic model that incorporated the Upper Jurassic–Cretaceous–Tertiary Composite Total Petroleum System of the Gulf of Mexico Basin. The following factors were evaluated to define the assessment unit and estimate undiscovered oil and gas resources: potential source rocks, hydrocarbon migration, reservoir porosity and permeability, traps and seals, structural features, depositional framework, and potential for water washing of hydrocarbons near outcrop areas. Analysis of the production history of discovered reservoirs and well data within the assessment unit was also essential for estimating the numbers and sizes of undiscovered oil and gas reservoirs within the assessment unit. The downdip boundary of the assessment unit was drawn as an arbitrary line 10 miles downdip of the Lower Cretaceous shelf margin, to include potential reef-talus reservoirs, a facies described in the geologic model developed for the assessment. Updip boundaries of the assessment unit were drawn based on the updip extent of assessment unit carbonate reservoir rocks, basin margin fault zones, and (or) the presence of producing wells within the assessed interval. Using the U.S. Geological Survey methodology, mean undiscovered resources of 40 million barrels of oil, 622 billion cubic feet of gas, and 14 million barrels of natural gas liquids were estimated for the assessment unit.

U.S. Gulf Coast↗

USGS2007

USGS assessment of undiscovered oil and gas resources in Paleogene strata of the U.S. Gulf of Mexico coastal plain and state waters

This report presents a review of the U.S. Geological Survey ( USGS ) 2007 assessment of the undiscovered oil and gas resources in Paleogene strata underlying the U.S. Gulf of Mexico Coastal Plain and state waters. Geochemical, geologic, geophysical, thermal maturation, burial history, and paleontologic studies have been combined with regional cross sections and data from previous USGS petroleum assessments have helped to define the major petroleum systems and assessment units. Accumulations of both conventional oil and gas and continuous coal-bed gas within these petroleum systems have been digitally mapped and evaluated, and undiscovered resources have been assessed following USGS methodology. The primary source intervals for oil and gas in Paleogene (and Cenozoic) reservoirs are coal and shale rich in organic matter within the Wilcox Group (Paleocene-Eocene) and Sparta Formation of the Claiborne Group (Eocene); in addition, Cretaceous and Jurassic source rocks probably have contributed substantial petroleum to Paleogene (and Cenozoic) reservoirs. For the purposes of the assessment, Paleogene strata have divided into the following four stratigraphic study intervals: (1) Wilcox Group (including the Midway Group and the basal Carrizo Sand of the Claiborne Group; Paleocene-Eocene); (2) Claiborne Group (Eocene); (3) Jackson and Vicksburg Groups (Eocene-Oligocene); and (4) the Frio-Anahuac Formations (Oligocene). Recent discoveries of coal-bed gas in Paleocene strata confirm a new petroleum system that was not recognized in previous USGS assessments. In total, 26 conventional Paleogene assessment units are defined. In addition, four Cretaceous-Paleogene continuous (coal-bed gas) assessment units are included in this report. Initial results of the assessment will be released as USGS Fact Sheets (not available at the time of this writing). Comprehensive reports for each assessment unit are planned to be released via the internet and distributed on CD-ROMs within the next year.

U.S. Gulf Coast↗