1,387 research outputs found
Power system design for a Jupiter solar electric propulsion spacecraft
Power system design for Jupiter solar electric propulsion spacecraf
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Sandstone distribution and potential for geopressured geothermal energy production in the Vicksburg formation along the Texas gulf coast
UT Librarie
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Geothermal Resources, Vicksburg Formation, Texas Gulf Coast
The potential for discovering geopressured geothermal reservoirs in the Vicksburg Formation is limited to Hidalgo County along the Lower Texas Gulf Coast. In Hidalgo County, an area of approximately 385 square miles (designated the Vicksburg Fairway) contains up to 1,300 feet of geopressured sandstones with fluid temperatures greater than 300Ă°F. In-place effective permeability, however, averages less than 1 millidarcy in the Vicksburg sandstones because of fine grain size and extensive late carbonate cementation. Also, the areal extent of individual reservoirs is limited in a dip direction by growth faults and in a strike direction by the lenticular morphology of the sandstone bodies.
In conclusion, under the present specifications set for a geothermal fairway, the Vicksburg has minimal potential because of low reservoir deliverability, which is constrained by low permeability and somewhat limited reservoir continuity. If future tests indicate that lower permeabilities are acceptable, the Vicksburg Fairway should be reconsidered because of the presence of extremely thick sandstone bodies.Bureau of Economic Geolog
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Effect of Hydrocarbon Production and Depressurization on Subsidence and Possible Fault Reactivation: Port Acres-Port Arthur Field Area, Southeast, Texas
Subsidence has been extensive in the coastal area of southeast Texas. Despite enormous hydrocarbon production in the area, however, most subsidence has been attributed more to regional shallow groundwater withdrawal than to hydrocarbon production. The impact of hydrocarbon production on subsidence can be accurately quantified only where the effects of groundwater withdrawal are minimal. The Port Acres and Port Arthur field area satisfies this requirement.
More than 380 Bcf of gas has been produced from the Port Acres and Port Arthur field area. Pressure in the Hackberry reservoir declined from an original 9,000 psi to less than 3,000 psi by the 1970s, then to less than 2,000 psi by the 1980s. The pressure drop from 9,000 to 1,000 psi could produce a maximum subsidence of 6 percent at reservoir depth. Assuming an average gas column of 50 to 120 ft, estimated compaction of the Hackberry reservoir is 2 to 5 ft (0.61 to 1.63 m), which is consistent with reported surface subsidence.Bureau of Economic Geolog
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Sandstone Consolidation Analysis to Delineate Areas of High Quality Reservoirs Suitable for Production of GeoPressured Geothermal Energy Along the Texas Gulf Coast
Analysis of reservoir quality of lower Tertiary sandstones along the Texas Gulf Coast delineatesareas most favorable for geopressured geothermal exploration. Reservoir quality is determined by whole core, acoustic log, and petrographic analyses.
Wilcox sandstones exhibit no regional reservoir quality trends. In the Lower and parts of the Middle and Upper Texas Gulf Coast, the sandstones are relatively well consolidated, but in other parts of the Middle and Upper Texas Gulf Coast, they show a reversal toward increased porosity at depth. Vicksburg sandstones have the poorest reservoir quality of sandstones of any formation prospective for geothermal energy. Frio sandstones show a systematic increase in reservoir quality from the Lower to the Upper Texas Gulf Coast. This increase in reservoir quality correlates to changes in rock composition and cementation. Acoustic log analysis substantiates a progression of greater consolidation from the Upper to the Lower Texas Gulf Coast.
Wilcox sandstones are poorly to moderately sorted, fine-grained, quartzose lithic arkoses, becoming more quartz-rich from the Upper to the Lower Texas Gulf Coast. Most rock fragments are metamorphic and volcanic. Vicksburg sandstones are poorly sorted, fine-grained lithic arkoses. Rock fragments are mainly volcanic clasts with lesser carbonate and minor metamorphic clasts. Frio sandstones range from poorly sorted, fine-grained, feldspathic litharenites to lithic arkoses in the Lower Texas Gulf Coast to poorly sorted, fine-grained, quartzose lithic arkoses to subarkoses in the Upper Texas Gulf Coast. Volcanic rock fragments predominate in all areas; carbonate rock fragments are common in the Lower Texas Gulf Coast.Bureau of Economic Geolog
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Geopressured Geothermal Fairway Evaluation and Test Well Site Location Frio Formation, Texas Gulf Coast
Tertiary strata of the Texas Gulf Coast comprise a number of terrigenous depositional wedges, some of which thicken abruptly at their downdip ends as a result of contemporaneous movement of growth faults and underlying salt. The Frio Formation, one of these wedges, has been studied regionally by means of a grid of correlation cross sections aided by micropaleontological control. By means of these sections, the Frio was subdivided into six map units; maps of sandstone distribution within these units delineate principal elongate sandstone trends parallel to the Gulf Coast composed of deltaic, barrier-bar, and strandplain sandstones.
These broad regional studies, followed by detailed local investigations, were pursued in order to delineate prospective areas for the production of geopressured geothermal energy. A prospective area must meet the following minimum requirements: reservoir volume of 3 cubic miles, minimum permeability of 20 millidarcys (md), and fluid temperatures of 300Ă°F. Several geothermal fairways were identified as a result of this Frio study.Bureau of Economic Geolog
Evidence-Based Professional Development of Science Teachers in Two Countries
The focus of this collaborative research project of King?s College London, and the Weizmann Institute, Israel. project is on investigating the ways in which teachers can demonstrate accomplished teaching in a specific domain of science and on the teacher learning that is generated through continuing professional development programs (CPD) that lead towards such practice. The interest lies in what processes and inputs are required to help secondary school science teachers develop expertise in a specific aspect of science teaching. `It focuses on the design of the CPD programmes and examines the importance of an evidence-based approach through portfolioconstruction in which professional dialogue pathes the way for teacher learning. The set of papers highlight the need to set professional challenge while tailoring CPD to teachers? needs to create the environment in which teachers can advance and transform their practice. The cross-culture perspective added to the richness of the development and enabled the researchers to examine which aspects were fundamental to the design by considering similarities and differences between the domains
Healthier prisons: The role of a prison visitors' centre
Since the inception of the prison as a âsettingâ for health promotion, there has been a focus on how the health of those men and women who spend âtime insideâ can at least be maintained and if possible, enhanced, during their prison sentence. This paper presents findings from a mainly qualitative evaluation of a prison visitors' centre in the UK. It reports experiences of prisoners' families, prisoners, prison staff, the local community and the ways in which the visitors' centre has contributed positively to their health and well-being. In addition, key stakeholders were interviewed to ascertain the role this visitors' centre has in policy frameworks related to re-offending. The findings from this evaluation underscore how the visitors' centre improved the quality of visits, and contributed towards the maintenance of family ties through the help and support it provides for families and prisoners. The paper concludes by suggesting that visitors' centres are an essential part of a modern prison service helping to address the government's health inequalities agenda
Water Resources Systems Planning and Management: An Introduction to Methods, Models and Applications
This 2005 version has been superseded by the 2017 edition, available in full here: http://hdl.handle.net/1813/48159Throughout history much of the world has witnessed
ever-greater demands for reliable, high-quality and
inexpensive water supplies for domestic consumption,
agriculture and industry. In recent decades there have
also been increasing demands for hydrological regimes
that support healthy and diverse ecosystems, provide for
water-based recreational activities, reduce if not prevent
floods and droughts, and in some cases, provide for the
production of hydropower and ensure water levels adequate
for ship navigation. Water managers are challenged
to meet these multiple and often conflicting demands. At
the same time, public stakeholder interest groups have
shown an increasing desire to take part in the water
resources development and management decision making
process. Added to all these management challenges
are the uncertainties of natural water supplies and
demands due to changes in our climate, changes in
people's standards of living, changes in watershed land
uses and changes in technology. How can managers
develop, or redevelop and restore, and then manage water
resources systems - systems ranging from small watersheds
to those encompassing large river basins and coastal
zones - in a way that meets society's changing objectives
and goals? In other words, how can water resources
systems become more integrated and sustainable
Making the most of data:An information selection and assessment framework to improve water systems operations
Advances in Environmental monitoring systems are making a wide range of data available at increasingly higher temporal and spatial resolution. This creates an opportunity to enhance real-time understanding of water systems conditions and to improve prediction of their future evolution, ultimately increasing our ability to make better decisions. Yet, many water systems are still operated using very simple information systems, typically based on simple statistical analysis and the operatorâs experience. In this work, we propose a framework to automatically select the most valuable information to inform water systems operations supported by quantitative metrics to operationally and economically assess the value of this information. The Hoa Binh reservoir in Vietnam is used to demonstrate the proposed framework in a multiobjective context, accounting for hydropower production and flood control. First, we quantify the expected value of perfect information, meaning the potential space for improvement under the assumption of exact knowledge of the future system conditions. Second, we automatically select the most valuable information that could be actually used to improve the Hoa Binh operations. Finally, we assess the economic value of sample information on the basis of the resulting policy performance. Results show that our framework successfully select information to enhance the performance of the operating policies with respect to both the competing objectives, attaining a 40% improvement close to the target trade-off selected as potentially good compromise between hydropower production and flood control
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