126 research outputs found

    Integrating Geophysics and Geochemistry to Evaluate Coalbed Natural Gas Produced Water Disposal, Powder River Basin, Wyoming.

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    Production of methane from thick, extensive coalbeds in the Powder River Basin of Wyoming has created water management issues. More than 4.1 billion barrels of water have been produced with coalbed natural gas (CBNG) since 1997. Infiltration impoundments, which are the principal method used to dispose CBNG water, contribute to the recharge of underlying aquifers. Airborne electromagnetic surveys of an alluvial aquifer that has been receiving CBNG water effluent through infiltration impoundments since 2001 reveal produced water plumes within these aquifers and also provide insight into geomorphologic controls on resultant salinity levels. Geochemical data from the same aquifer reveal that CBNG water enriched in sodium and bicarbonate infiltrates and mixes with sodium-calcium-sulfate type alluvial groundwater, which subsequently may have migrated into the Powder River. The highly sodic produced water undergoes cation exchange reactions with native alluvial sediments as it infiltrates, exchanging sodium from solution for calcium and magnesium on montmorillonite clays. The reaction may ultimately reduce sediment permeability by clay dispersion. Strontium isotope data from CBNG wells discharging water into these impoundments indicate that the Anderson coalbed of the Fort Union Formation is dewatered due to production. Geophysical methods provide a broad-scale tool to monitor CBNG water disposal especially in areas where field based investigations are logistically prohibitive, but geochemical data are needed to reveal subsurface processes undetectable by geophysical techniques. The results of this research show that: (1) CBNG impoundments should not be located near streams because they can alter the surrounding hydraulic potential field forcing saline alluvial groundwater and eventually CBNG water into the stream, (2) point bars are poor impoundment locations because they are essentially in direct hydraulic communication with the associated stream and because plants readily transpire shallow groundwater within them creating vadose zone salt accumulations that will be dissolved by infiltrating CBNG water, and (3) cation exchange reactions in vadose zone sediments may reduce soil permeability beneath infiltration impoundments through clay dispersion lowering their designed disposal capacity

    Proceedings of the 2009 Coal Operators\u27 Conference

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    Proceedings of the 2009 Coal Operators\u27 Conference. All papers in these proceedings are peer reviewed. ISBN: 978 1 920806 95 8

    Advances in Theoretical and Computational Energy Optimization Processes

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    The paradigm in the design of all human activity that requires energy for its development must change from the past. We must change the processes of product manufacturing and functional services. This is necessary in order to mitigate the ecological footprint of man on the Earth, which cannot be considered as a resource with infinite capacities. To do this, every single process must be analyzed and modified, with the aim of decarbonising each production sector. This collection of articles has been assembled to provide ideas and new broad-spectrum contributions for these purposes

    Bureau of Mines publications and articles, 1992-1993 (with subject and author index)

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    The U.S. Bureau of Mines (USBM) was established in the public interest to conclude inquiries and scientific and technologic investigations on mining and the preparation, treatment, and utilization of mineral substances; to promote health and safety in the mineral industries; to conserve material resources and prevent their waste; to further economic development; to increaseee efficiency in the mining, metallurgical, quarrying, and other mineral industries; and to inquire into the economic conditions affecting those industries. The organic act of the Bureau, as amended by Congress and approved February 25, 1913, made it the province and duty of the U.S. Bureau of Mines to "disseminate information concerning these subjects in such manner as will best carry out the purposes of this Act."In accordance with this directive, USBM reports the findings of its research and investigations in its own series of publications and also in articles that appear in scientific, technical, and trade journals; in proceedings of conventions and seminars; in reference books; and in other non-USBM publications. The number of these reports, the wide range of subjects they cover, and the variety of mediums in which they appear make this kind of list both necessary and valuable.This edition describes reports and articles published during calendar years 1992 and 1993. It supplements the 50-year list of Bureau publications from July 1, 1910, to January 1, 19602 ; and these 5-year lists of publications and articles: from January 1, 1965, to December 31, 1969 from January 1, 1970, to December 31, 1974, from January 1, 1975, to December 31, 197 , from January 1, 1980, to December 31,1984, and from January 1, 1985, to December 31, 1989.ISBN 0-16-045065-

    Report of the Nova Scotia Independent Panel on Hydraulic Fracturing

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    On August 28, 2013, the Province of Nova Scotia and the Nova Scotia Department of Energy signed an agreement with the Verschuren Centre for Sustainability in Energy and the Environment at Cape Breton University to conduct an external review on the environmental, socio-economic, and health impacts of hydraulic fracturing. Simultaneously, Dr. David Wheeler, President and Vice Chancellor of Cape Breton University, was asked to convene and Chair the review and expert panel on a voluntary and unpaid basis.1 The mandate for the review was to: create a panel of technical experts based on input from the public and hire technical consultant(s) to facilitate the work of the panel; hire a part-time project administrator; conduct public consultations on the process of hydraulic fracturing with online tools and face-to-face meetings with stakeholders; and conduct a literature review on the health and socio-economic impacts of hydraulic fracturing. These activities would result in a final report to the Government of Nova Scotia with recommendations on the potential of hydraulic fracturing to develop unconventional gas and oil resources in the Province. The scope of work included, but was not limited to, the following areas of research: effects on groundwater - including both water quality and quantity issues; effects on surface water; impacts on land; management of additives to hydraulic fracturing fluids; waste management; site restoration; requirements for hydraulic fracturing design including chemicals used; and the engineered design and financial security considerations that operators are required prior to conducting activity in the Province. The intended outcome for the project was for the Province of Nova Scotia to be able to make an informed decision on the future of hydraulic fracturing activity in Nova Scotia, based on input from technical experts and the public on environmental, health, and socio-economic impacts. The original end date for the review was June 30, 2014, but the deadline was extended until August 31, 2014

    Proceedings of the 2017 Coal Operators\u27 Conference

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    Proceedings of the 2017 Coal Operators\u27 Conference. All papers in these proceedings are peer reviewed. ISBN: 978174128261

    Evaluation Of CO2 Flooding In Tight Formation

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    The low recovery of oil from the tight liquid-rich formations is still a main challenge for the tight reservoir. Thus, in order to break the chains and remove the obstacle such as the low recovery factor in the Bakken tight formation, even though the horizontal drilling and hydraulic fracturing technologies were already well applied in this field, the supercritical CO2 flooding was proposed as an immense potential recovery method for the production improvement. In this research, we conducted a series of CO2 flooding experiments under various injection pressure (2500psi, 2800psi, 3000psi, 3500psi), to investigate the recovery potential of the core sample from Bakken tight formation. Also, the NMR analysis was processed of the core samples flooded with CO2 agent under the above injection pressure variables. The result comparison demonstrates that, with the supercritical CO2 injection pressure increase, the recovery factor gets incremental trend from 8.8% up to 33% recovery. Also, the macro pore and natural fracture system were proved to contribute more on the recovery potential. After reaching the miscible phase between the CO2 and oil in the sample, the hydrocarbon existed in the micro pores start the contribution to the recovery potential. Thus, The CO2 was identified as a potential recovery agent and the supercritical CO2 EOR method was proposed as the potential recovery technology due to the high recovery factor obtained in the immiscible and miscible processes. Up to date, rare study was put forward to account for the formation properties variation during the CO2 EOR process, especially the investigation at the micro-scale. This work conducted a series of measurements to evaluate the rock mechanical change, mineral alteration and the pore structure properties variation through the supercritical CO2 (Sc-CO2) injection process. Corresponding to the time variation (0 days, 10 days, 20 days, 30 days and 40 days), the rock mechanical properties were analyzed properly through the nano-indentation test, and the mineralogical alterations were quantified through the X-Ray diffraction (XRD). In addition, pore structures of the samples were measured through the low-temperature N2 adsorption tests. The results showed that, after Sc-CO2 injection, Young’s modulus of the samples decreases. The nitrogen adsorption results demonstrated that, after the CO2 injection, the mesopore volume of the sample changes as well as the specific surface area (BET) which rises from the chemical reactions between the CO2 and some authigenic minerals. XRD analysis results also indicated that mesopores were altered due to the chemical reaction between the injected Sc-CO2 and the minerals. Also, with existence of the natural fracture and the hydraulic fracture in the Bakken formation, it becomes more and more crucial to quantify the fracture system precisely and reconstruct the structure system in order to identify the preferential flow channels for the fluid flow, such as figuring out the domain pass way of the supercritical CO2. Up to date, the imaging technologies for the fracture quantization and reconstruction of the tight rock is still challenged by the ineffective segmentation, thus significantly influence the fracture properties calculation, including the porosity, aperture, openness, etc. In this research, a novel image processing method was proposed and certificated. By definition, the multi-stage image segmentation (MSS) method can separate the fracture system from the background by combining the global information and local information of the X- ray CT image. Through employing the entropy function and indicator kriging method, the generated three-dimensional model overcome the over– and in-sufficient segmentation due to the tiny fracture apertures and could provide visualization of the fracture systems existing in the core. Also, the important parameters of the fractures can be obtained, including aperture, length, tortuosity, and porosity. All the obtained parameters are beneficial to fracture identification during the CO2 EOR process in the Bakken tight formation

    List of Bureau of Mines publications and articles, January 1, 1960, to December 31, 1964 with subject and author index

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    The Bureau of Mines was establis4ed in the public interest to conduct inquiries and scientific and technologic investigations concerning mining and the preparation, treatment, and utilization of mineral substances; to promote health and safety in the mineral industries; to conserve mineral resources and prevent their waste; to further economic development; to increase efficiency in the mining, metallurgical, quarrying, and other mineral industries; and to inquire into the economic conditions affecting these industries. The organic act of the Bureau, as amended by Congress and approved February 25, 1913, made it the province and duty of the Bureau to "disseminate information concerning these subjects 'in such manner as will best carry out the purposes of this Act.\ue2\u20ac?In accordance with that directive, the Bureau reports the findings of its research and investigations in its own series of publications and also in articles that appear in scientific, technical, and trade journals; in proceedings of conventions and seminars; in reference books; and in other non-Bureau sources. The number of these reports, the wide range of subjects they cover, and the variety of mediums in which they appear make the kind of list and index presented in this special publication both necessary and valuable. This issue describes Bureau reports and articles published during the period January 1, 1960 to December 31, 1964. It supplements the 50-year list of Bureau publications issued from July 1, 1910, to January 1, 1960, and the 50-year list of articles by Bureau authors published outside the Bureau from July 1, 1910, to January 1, 1960. It supersedes the annual lists of Bureau publications and articles from January 1 to December 31, 1960, from January 1 to December 31, 1961, from January 1 to December 31, 1962, and from January 1 to December 31, 1963.7The leading general and technical libraries of the United States maintain files of the Bureau's publications. A list of these libraries appears immediately following this introduction

    Aircraft-based measurements for the identification and quantification of sources and sinks in the carbon cycle

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    Improved quantification of carbon-cycle sources and sinks is an important requirement for determining mitigation strategies and modeling future climate interactions. Analytically robust measurements require high-precision instrumentation and thoughtful experimental design to produce rigorous and reproducible results despite complex and quickly changing meteorological and environmental conditions. Here, an aircraft platform equipped with a high-precision cavity ring-down spectrometer for CO2, CH4 and H2O quantification was used to acquire data from previously un-sampled sources. The aircraft mass-balance technique was used to quantify CH4 emissions from natural gas well pads in the drilling stage, which were 2-3 orders of magnitude higher than previous estimates of emissions from this stage. In addition, the first in-situ flare emission data was collected for natural gas flares in North Dakota, Pennsylvania and Texas. Flare efficiency was high for most flares, higher than assumed efficiency. However, a few flares sampled with lower efficiencies closer to the assumed flare efficiency suggest the need for characterization of operational conditions specific to operators and basins. Finally, eddy-covariance O2 and heat fluxes were measured over three east-coast forests at sites close to and far from surface eddy-covariance towers. Tower data is often used in models to represent a larger heterogeneous region. Aircraft and tower O2 and sensible heat flux agreed well, indicating that for these sites, tower data is a good approximation of the larger region, though significant variability was observed. Aircraft latent heat fluxes were routinely much larger that tower fluxes, most likely due to the influence of advection which is measured by the aircraft eddy-covariance technique, but not by towers

    Multi-scale permeability of coal fractures and cleats

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