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Trends in thermal maturity indicators for the organic sulfur-rich Eagle Ford Shale

Thermal maturity is critical to evaluate petroleum systems and to interpret biomarker results for paleoenvironmental and geobiology studies. Many thermal maturity indices were developed for marine source rocks containing type II kerogen, but their behavior in organic sulfur-rich source rocks requires more investigation. Here, we present geochemical analyses of whole and extracted rock, isolated ke
Authors
Katherine L. French, Justin E. Birdwell, Michael Lewan

Detrital zircon age spectra of middle and upper Eocene outcrop belts, U.S. Gulf Coast region

Recently reported detrital zircon (DZ) data help to associate the Paleogene strata of the Gulf of Mexico region to various provenance areas. By far, recent work has emphasised upper Paleocene-lower Eocene and upper Oligocene strata that were deposited during the two episodes of the highest sediment supply in the Paleogene. The data reveal a dynamic drainage history, including (1) initial routing o
Authors
William H. Craddock, James L. Coleman Jr., Andrew R.C. Kylander-Clark

Compositional analysis of formation water geochemistry and microbiology of commercial and carbon dioxide-rich wells in the southwestern United States

Studies of naturally occurring subsurface carbon dioxide (CO2) accumulations can provide useful information for potential CO2 injection projects; however, the microbial communities and formation water geochemistry of most reservoirs are understudied. Formation water and microbial biomass were sampled at four CO2-rich reservoir sites: two within Bravo Dome, a commercial CO2 field in New Mexico; one
Authors
Jenna L. Shelton, Robert S. Andrews, Denise M. Akob, Christina A. DeVera, Adam C. Mumford, Mark Engle, Michelle R. Plampin, Sean T. Brennan

Mineralogy and lithology of the Upper Cretaceous Niobrara Formation determined by hyperspectral core imaging

Sections of the Upper Cretaceous (Coniacian to Campanian) Niobrara Formation in two cores from Kansas and Colorado, the Amoco Rebecca Bounds and USGS Portland 1, respectively, were examined by hyperspectral core imaging and analysis. A spectral imaging system combining high-resolution photography (50 μm), 3D laser profiling (20 μm), and near-visible + short-wave infrared reflectance spectroscopy (
Authors
Justin E. Birdwell, Lionel C. Fontenot, Brigette Martini

A two-stage step-wise framework for fast optimization of well placement in coalbed methane reservoirs

Coalbed methane (CBM) has emerged as a clean energy resource in the global energy mix, especially in countries such as Australia, China, India and the USA. The economical and successful development of CBM requires a thorough evaluation and optimization of well placement prior to field-scale exploitation. This paper presents a two-stage, step-wise optimization framework to obtain the optimal placem
Authors
Jiyuan Zhang, Qihong Feng, Xianmin Zhang, Jia Bai, C. Özgen Karacan, Derek Elsworth

Assessment of continuous oil and gas resources in Lower Silurian Shales of the Arabian Peninsula, 2019

Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 4.6 billion barrels of oil and 561 trillion cubic feet of gas in the Lower Silurian Shale Total Petroleum System of the Arabian Peninsula.
Authors
Christopher J. Schenk, Tracey J. Mercier, Cheryl A. Woodall, Marilyn E. Tennyson, Thomas M. Finn, Michael E. Brownfield, Kristen R. Marra, Phuong A. Le, Ronald M. Drake, Scott A. Kinney

Sample mounting for organic petrology: No thermal effects from transient exposure to elevated temperatures

For sample mounting, organic petrology laboratories typically use cold-setting epoxy-resin (e.g., 40 °C, used by Oklahoma Geological Survey, OGS) or heat-setting thermoplastic (e.g., 180 °C, used by U.S. Geological Survey, USGS). Previous workers have suggested a systematic huminite/vitrinite reflectance (VRo) increase was associated with the thermoplastic preparation process, relative to epoxy mo
Authors
Paul C. Hackley, Brian J. Cardott

Fluorescence spectroscopy of ancient sedimentary organic matter via confocal laser scanning microscopy (CLSM)

Fluorescence spectroscopy via confocal laser scanning microscopy (CLSM) was used to analyze ancient sedimentary organic matter, including Tasmanites microfossils in Devonian shale and Gloecapsomorpha prisca (G. prisca) in Ordovician kukersite from North American basins. We examined fluorescence emission as a function of excitation laser wavelength, sample orientation, and with respect to location
Authors
Paul C. Hackley, Aaron M. Jubb, Robert Burruss, Amy E Beaven

Assessment of tight-gas resources in the Grand Erg/Ahnet Province of Algeria, 2019

Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 30.5 trillion cubic feet of tight gas in the Grand Erg/Ahnet Province of Algeria.
Authors
Michael E. Brownfield, Christopher J. Schenk, Tracey J. Mercier, Marilyn E. Tennyson, Cheryl A. Woodall, Thomas M. Finn, Phuong A. Le, Janet K. Pitman, Ronald M. Drake, Stephanie B. Gaswirth, Heidi M. Leathers-Miller

Well predictive performance of play-wide and Subarea Random Forest models for Bakken productivity

In recent years, geologists and petroleum engineers have struggled to clearly identify the mechanisms that drive productivity in horizontal, hydraulically-fractured oil wells producing from the middle member of the Bakken formation. This paper fills a gap in the literature by showing how this play’s heterogeneity affects factors that drive well productivity. It is important because understanding t
Authors
Emil D. Attanasi, Philip A. Freeman, Tim Coburn

Surface to subsurface correlation of the Middle-Upper Triassic Shublik Formation within a revised sequence stratigraphic framework

Recent work on cores and outcrops of the Middle-Upper Triassic Shublik Formation has facilitated surface to subsurface correlation of depositional sequences across the Alaska North Slope. Five transgressive-regressive depositional sequences have been defined within three large-scale stratigraphic units. Outcrop spectral gamma-ray (GR) profiles were used to correlate observed stacking patterns with
Authors
William A. Rouse, Katherine J. Whidden, Julie A. Dumoulin, David W. Houseknecht

Units recovery methods in compositional data analysis

Compositional data carry relative information. Hence, their statistical analysis has to be performed on coordinates with respect to a log-ratio basis. Frequently, the modeler is required to back-transform the estimates obtained with the modeling to have them in the original units such as euros, kg or mg/liter. Approaches for recovering original units need to be formally introduced and its properti
Authors
J. A Martin-Fernandez, Juan Jose Egozcue, Ricardo A. Olea, Vera Pawlowsky-Glahn