Abstract:The two methods of processing synthetic crude from organic marlstone in demonstration or small-scale commercial status in the U.S. are in situ extraction and surface retorting. The considerable uncertainty surrounding the technological characterization, resource characterization, and choice of the system boundary for oil shale operations indicate that oil shale is only a minor net energy producer if one includes internal energy (energy in the shale that is used during the process) as an energy cost. The energy return on investment (EROI) for either of these methods is roughly 1.5:1 for the final fuel product. The inclusions or omission of internal energy is a critical question. If only external energy (energy diverted from the economy to produce the fuel) is considered, EROI appears to be much higher. In comparison, fuels produced from conventional petroleum show overall EROI of approximately 4.5:1. "At the wellhead" EROI is approximately 2:1 for shale oil (again, considering internal energy) and 20:1 for petroleum. The low EROI for oil shale leads to a significant release of greenhouse gases. The large quantities of energy needed to process oil shale, combined with the thermochemistry of the retorting process, produce carbon dioxide and other greenhouse gas emissions. Oil shale unambiguously emits more greenhouse gases than conventional liquid fuels from crude oil feedstocks by a factor of 1.2 to 1.75. Much of the discussion regarding the EROI for oil shale should be regarded as preliminary or speculative due to the very small number of operating facilities that can be assessed.
Economic and social factors compel large-scale changes in energy systems. An ongoing transition in the United States is driven by environmental concerns, changing patterns of energy end-use, constraints on petroleum supply. Analysis of prior transitions shows that energy intensity in the U.S. from 1820 to 2010 features a declining trend when traditional energy is included, in contrast to the "inverted U-curve" seen when only commercial energy is considered. This analysis quantifies use of human and animal muscle power, wind and water power, biomass, harvested ice, fossil fuels, and nuclear power, with some consumption series extending back to 1780. The analysis reaffirms the importance of innovation in energy conversion technologies in energy transitions. An increase in energy intensity in the early 20th century is explained by diminishing returns to pre-electric manufacturing systems, which produced a transformation in manufacturing. In comparison to similar studies for other countries, the U.S. has generally higher energy intensity.
The UCD community has made this article openly available. Please share how this access benefits you. Your story matters! (@ucd_oa) Some rights reserved. For more information, please see the item record link above. ABSTRACT Marine clay deposits in coastal, post-submarine areas of Scandinavia and North America may be subjected to quick clay landslides and hence significant efforts are being taken to map their occurrence and extent. The purpose of this paper is to assess the use of a number of geophysical techniques for identifying quick clay. The investigated area, Smørgrav, located in southern Norway has a history of quick clay sliding, the most recent event occurring in 1984. Geophysical techniques that are used include electromagnetic conductivity mapping, electrical resistivity tomography, seismic refraction and multichannel analysis of surface waves. These results are compared to geotechnical data from bore samples, rotary pressure soundings and cone penetration testing. A number of these approaches have proved promising for identifying quick clay, in particular electrical resistivity tomography and electromagnetics, which delineated a zone of quick clay that had previously been confirmed by rotary pressure soundings and sampling. Seismic refraction was useful for determining the sediment distribution as well as for indicating the presence of shallow bedrock whereas the multichannel analysis of surface-waves approach suggested differences between the intact stiffness of quick and unleached clay. It is observed that quick clay investigations using discrete rotary pressure soundings can be significantly enhanced by using, in particular, electrical resistivity tomography profiles to link together the information between test locations, perhaps significantly reducing the need for large numbers of soundings.
I certify that I have read this report and that in my opinion it is fully adequate, in scope and in quality, as partial fulfillment of the degree of Master of Science in Petroleum Engineering.
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