Geology topics
Publications and source records attributed to Geoffrey S. Ellis.
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean conventional resources of 7.3 billion barrels of oil and 463.7 trillion cubic feet of gas within the Barents Sea area.
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 321 million barrels of shale oil and 435 billion cubic feet of shale gas in the Lower Saxony Basin, Germany.
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 13,929 million (13.9 billion) barrels of oil and 193,721 billion (193.7 trillion) cubic feet of gas within the Senegal Basin Province of northwest Africa.
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean conventional resources of 4.9 billion barrels of oil and 21 trillion cubic feet of gas within the Volga-Ural Basin Province and technically recoverable mean conventional resources of 1.8 billion barrels of oil and 9.5 trillion cubic of gas in the Timan-Pechora Basin Province, Russia.
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered resource means of 1.8 billion barrels of oil and 129.5 trillion cubic feet of gas within New Guinea, Papua Barat, Seram, and Timor-Leste.
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean conventional resources of 12.9 billion barrels of oil and 684.3 trillion cubic feet of gas in the West Siberian Basin Province of Russia.
Using a geology-based assessment methodology, the U.S. Geological Survey estimated means of 783 million barrels of conventional oil and 17,606 billion (17.6 trillion) cubic feet of conventional gas in the Montana Thrust Belt Province.
Lake Tanganyika ranks among the most valuable modern analogs for understanding depositional processes of carbonaceous sediments in ancient tropical rifts. Prior research on Lake Tanganyika has emphasized the importance of bottom-water anoxia, depositional processes (hemipelagic settling versus gravity flows), and large-scale (100s of meters) lake level change on the quality of sedimentary organic matter content. Here, facies analysis and numerous organic geochemical tools (elemental, carbon isotope, and programmed pyrolysis) were applied to a radiocarbon-dated core from southern Lake Tanganyika to investigate the accumulation of carbonaceous sediments in a deepwater slope environment influenced by high-frequency climatic fluctuations accompanied by only minor (10s of meters) lake level changes. Considerable variability in lithofacies and geochemistry characterizes the ∼ 1030-year-long core record, chiefly driven by climate-mediated changes to the lake's upwelling system. Laminated diatom oozes and sapropels with mean total organic carbon (TOC) concentrations and hydrogen indices of 6.9 wt.% and 385 mg hydrocarbon/g TOC, respectively, characterize sediments deposited during periods of strong upwelling and variable water levels. Silty sediments deposited via gravity-flow processes were likewise rich in organic matter, likely due to preservation-enhancing bottom-water anoxia. Dilution by reworked tephra was the chief constraint on organic enrichment at the study site. Data from this study reveal that oscillations in atmospheric and limnological processes in the absence of major shoreline movements can result in geochemically diverse deepwater slope sediments, which have implications for improving depositional models of petroliferous continental rift basins.
Using a geology-based assessment methodology, the U.S. Geological Survey estimated means of 806 million barrels of oil and 17.0 trillion cubic feet of gas within the greater Taranaki Basin and East Coast Basin of New Zealand.
A suite of gas standards was developed to serve as international secondary reference materials (RMs) for the determination of the compound-specific carbon-13/carbon-12 ( δ 13 C) and hydrogen-2/hydrogen-1 ( δ 2 H) values of hydrocarbon gases. This report provides background information on the project, the methods used to produce and analyze the gases, as well as the data analysis and recommended stable isotopic values. Additionally, samples of older hydrocarbon gas RMs no longer available were analyzed along with the new RMs to allow for traceability to historical data. These secondary RMs are intended for interlaboratory standardization and traceability to primary RMs. The gaseous RMs are currently (at time of publication) available for purchase from the U.S. Geological Survey Energy Resources Program.
The objective of this work is to characterize the geochemistry of a suite of natural gas samples from five fields in order to improve the understanding of the lacustrine petroleum system of the pre-salt section from the Santos Basin (Brazil). Additionally, the distribution of volatile organic sulfur compounds (VOSC) in petroleum reservoirs was examined to investigate possible applications to petroleum systems assessments. The hydrocarbon gases were generated by thermogenic processes associated with the oil window. The 13 C-enriched values for C 1 (>−40‰) were interpreted as an organic source signature rather than an indication of thermal maturity, except for the oil occurrence (Field B), where a different fluid charge mainly composed of methane and CO 2 from a minor external kitchen area in the Santos Basin was identified. The molecular composition and the carbon and hydrogen isotopic data of the hydrocarbon gases, when combined with the VOSC molecular compositional data, allow the identification of four gas families associated with different kitchens and/or migrations pathways. The total VOSC concentrations range from 0.7 to 23.9 ppm by volume (ppmV). The organic sulfides are mainly composed of carbonyl sulfide (COS) and diethyl sulfide. The main thiol compound is ethanethiol. The cyclic VOSC are primarily composed of thiophene, with a negligible amount of branched thiophenes (<0.1 ppmV). H2S showed a strong positive Pearson's correlation with COS and methanethiol (MeSH) concentrations (r = 0.943 and 0.807, respectively). This suggests that COS and MeSH formation was linked to H 2 S generation and/or post-catagenetic interactions between hydrocarbons and H 2 S, mainly related to thermochemical sulfate reduction (TSR). In contrast, the distribution of higher molecular weight VOSC seems to be controlled by source rock facies, rather than H 2 S concentration. Principal component analysis of the VOSC compositional data identified some subgroups within the gas families mainly associated with TSR. The results presented in this work reveal that VOSC can be an important auxiliary tool in petroleum system studies.
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 4.3 billion barrels of oil and 4.9 trillion cubic feet of gas (associated) in the Bakken and Three Forks Formations of the Williston Basin Province, North Dakota and Montana.
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 13.4 billion barrels of oil and 244.4 trillion cubic feet of gas in nine geologic provinces of China.
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 83 million barrels of oil and 351 billion cubic feet of gas in lower Paleozoic strata of the Williston Basin Province, North Dakota, Montana, and South Dakota.
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 161 million barrels of oil and 93 billion cubic feet of gas in the Tyler Formation of the Williston Basin Province, North Dakota.
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean oil and gas resources of 134 million barrels of oil and 81 billion cubic feet of gas in upper Paleozoic strata of the Williston Basin Province in North Dakota, Montana, and South Dakota.
Using a geology-based assessment methodology, the U.S. Geological Survey estimated a mean of 2,438 billion (2.4 trillion) cubic feet of gas resources in the Williston Basin Province, in North Dakota, Montana, and South Dakota.
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 288 million barrels of oil and 2.6 trillion cubic feet of gas in the Mowry Shale in the Wind River Basin Province, Wyoming.