Geology topics

Brett J. Valentine

Publications and source records attributed to Brett J. Valentine.

39 records · Page 3Linked to original sources

USGS2012

Shallow coal exploration drill-hole data--Alabama, Georgia, Kentucky, Louisiana, Mississippi, Missouri, North Carolina, South Carolina, Tennessee, and Texas

Coal exploration drill-hole data from over 24,000 wells in 10 States are discussed by State in the chapters of this report, and the data are provided in an accompanying spreadsheet. The drill holes were drilled between 1962 and 1984 by Phillips Coal Company, a division of Phillips Petroleum Company (Phillips). The data were donated to the U.S. Geological Survey (USGS) in 2001 by the North American Coal Corporation, which purchased the Phillips assets as part of a larger dataset. Under the terms of the agreement with North American Coal Corporation, the data were deemed proprietary until February 2011, a period of 10 years after the donation (Appendix of Chapter A). Now that the required period of confidentiality has passed, the data have been digitized from tabulated data files to create unified and spatially consistent coal exploration drill-hole maps and reports for the States of Alabama, Georgia, Kentucky, Louisiana, Mississippi, Missouri, North Carolina, South Carolina, Tennessee, and Texas. The data are made publicly available by this report.

Alabama; Georgia; Kentucky; Louisiana; Mississippi↗

USGS2012

Preliminary evaluation of the shale gas prospectivity of the Lower Cretaceous Pearsall Formation in the onshore Gulf Coast region, United States

Recent work by the U.S. Geological Survey indicated that the Lower Cretaceous Pearsall Formation contains an estimated mean undiscovered, technically recoverable unconventional gas resource of 8.8 trillion cubic ft in the Maverick Basin, South Texas. Cumulative gas production from horizontal wells in the core area of the emerging play has exceeded 5 billion cubic ft since 2008. However, very little information is available to characterize the Pearsall Formation as an unconventional gas resource beyond the Maverick Basin in the greater Gulf Coast region. Therefore, this reconnaissance study examines spatial distribution, thickness, organic richness and thermal maturity of the Pearsall Formation in the onshore U.S. Gulf states using wireline logs and drill cuttings sample analysis. Spontaneous potential and resistivity curves of approximately forty wireline logs from wells in five Gulf Coast states were correlated to ascertain the thickness of the Pearsall Formation and delineate its three members: Pine Island Shale, James Limestone or Cow Creek Limestone, and Bexar Shale, in ascending stratigraphic order. In Florida and Alabama the Pearsall Formation is up to about 300 ft thick; in Mississippi, Louisiana, Arkansas, and East Texas, thickness is up to as much as 800 ft. Drill cuttings sampled from 11 wells at depths ranging from 4600 to 19,600 feet subsurface indicate increasingly oxygenated depositional environments (predominance of red shale) towards the eastern part of the basin. Cuttings vary widely in lithology but indicate interbedded clastics and limestones throughout the Pearsall Formation, consistent with previous regional studies. Organic petrographic and geochemical analyses of 17 cutting samples in the Pearsall Formation indicate a wide range in thermal maturity, from immature (0.43% Ro [vitrinite reflectance]) in paleo-high structural locations to the peak oil window (0.99% Ro) in the eastern portion of the Gulf Coast Basin. This is in contrast to dry gas thermal maturity throughout the Pearsall Formation in the South Texas Maverick Basin. Organic carbon content is low overall, even in immature samples, with a range of 0.17 to 1.08 wt.% by Leco in 22 Pearsall Formation samples. The pyrolysis output range was 0.23 to 2.33 mg hydrocarbon/g rock. The thermal maturity and Rock-Eval pyrolysis data and organic petrologic observations from this study will be used to better focus specific areas of investigation where the Pearsall Formation may be prospective as an unconventional hydrocarbon source and reservoir.

Alabama;Arkansas;Louisiana;Mississippi;Oklahoma;Te↗

USGS2010

Geology and assessment of undiscovered oil and gas resources in Mesozoic (Jurassic and Cretaceous) rocks of the onshore and state waters of the Gulf of Mexico Region, U.S.A

The U.S. Geological Survey (USGS) is in the final phase of the most recent assessment of the undiscovered technically recoverable oil and gas resources of the U.S. Gulf of Mexico coastal plain and state waters. Ongoing geologic, geochemical, and petrophysical framework studies have defined the total petroleum systems and assessment units (AUs) in the Gulf Coast region. Current studies examine the Mesozoic (Jurassic and Cretaceous) source rocks and reservoir units, and recent studies have assessed the undiscovered resources in Tertiary and certain Jurassic and Cretaceous units. The Upper Jurassic and Lower Cretaceous Cotton Valley Group and Lower Cretaceous Hosston and Travis Peak formations, as well as the Upper Cretaceous Taylor and Navarro groups and the Tuscaloosa and Woodbine groups downdip shelf-margin deltas, were assessed in 2006. Tertiary strata were assessed in 2007. Jurassic strata presently under evaluation include the Upper Jurassic Norphlet, Smackover, Haynesville, and Bossier formations. Lower Cretaceous units to be assessed in the present study include the Knowles Limestone, Sligo Formation, Trinity Group, Fredericksburg Group, and lower part of the Washita Group. Upper Cretaceous rocks being assessed include the Buda Limestone of the Washita Group, Eagle Ford Group (Eagle Ford shale, and the updip Tuscaloosa and Woodbine groups), Austin Chalk (Group), and Tokio and Eutaw formations. For each AU, a geologic model is developed to define hydrocarbon source, charge, migration, trap, and reservoir, and to estimate technically recoverable undiscovered oil and gas resources. The USGS assessment is focused on evaluating conventional clastic and carbonate deposystems, as well as resource volumes in emerging unconventional gas, shale gas, and shale oil plays currently attracting global attention.

Texas, Louisiana, Alabama, Mississippi, Florida↗