Thesis (Ph. D.)--University of Adelaide, Dept. of Geology and Geophysics, 1987. / Includes bibliographical references (leaves 137-158).

Thesis (Ph. D.)--University of Washington, 1999. / Includes bibliographical references (p. [77]-86).

Understanding the controls on fluid migration in reservoir rocks is becoming evermore important within the petroleum industry as significant hydrocarbon discoveries become less frequent and more emphasis is placed on enhanced oil recovery methods. To fully understand the factors controlling fluid migration in the subsurface, pore scale information is necessary. In this study, synchrotron-based X-ray computed microtomography (CMT) is being utilized to extract physically realistic images of carbonate rock cores for the evaluation of porosity and mineralogy in the Mississippian Midale beds of the Weyburn Oilfield in southeastern Saskatchewan. Non-destructive in-situ imaging by CMT is unique as it provides a detailed and novel approach for the description of pore space geometry, while preserving connectivity and spatial variation of pore-body and pore-throat sizes. Here, three-dimensional micron to sub-micron (0.3ìm-100ìm) resolution of CMT is coupled with, and compared against, conventional laboratory-based methods (liquid and gas permeametry, mercury injection porosimetry, electrical resistivity, backscattered electron (BSE) from electron probe micro-analysis (EPMA) and transmitted light microscopy). Petrophysical and mineralogical information obtained from both CMT and conventional methods will have direct implications for understanding the petrophysical mechanisms that control fluid movement in the subsurface of the Weyburn Oilfield.<p>At Weyburn, CO2 gas is being injected into producing horizons to enhance oil recovery and permanently sequester CO2 gas. Fundamental questions exist regarding: (1) The significance of pore geometry and connectivity to the movement of CO2 and other fluids in the subsurface, (2) the nature of the interactions between CO¬2 and pore lining minerals and their impact on petrophysical properties, and (3) the distribution and mineralogy of finely disseminated silicate and carbonate minerals adjacent to pore spaces as interaction among these phases and CO2 may result in permanent sequestration of CO2. <p>The two producing horizons within the Weyburn Reservoir, the Midale Marly and Midale Vuggy units, have variable porosities and permeabilities. Porosity in the Marly unit ranges from 16% to 38% while permeability ranges from 1mD to greater than 150 mD across the field. For the Vuggy unit, porosity ranges from 8% to 21% with permeability ranging from 0.3mD to 500mD. Using CMT, pore space is critically examined to highlight the controlling factors on permeability. Digital processing of CMT data indicates that pore space in the Marly unit is dominated by intercrystalline pores having diameters of approximately 4 ìm. From here, it is noted that the pore-throat radii are approximately ½ the radii of the pore-bodies, having profound implications to current oil recovery methods. Tortuosity values from CMT are also observed to have similar values in three orthogonal directions indicating an isotropic pore space distribution within the Marly unit. Alternatively, the Vuggy unit is found to possess greater pore-body and pore-throat sizes that are heterogeneous in distribution. Based on this, permeability in the Vuggy unit is strongly dependant on pore-length scales that vary drastically between localities.

Understanding the controls on fluid migration in reservoir rocks is becoming evermore important within the petroleum industry as significant hydrocarbon discoveries become less frequent and more emphasis is placed on enhanced oil recovery methods. To fully understand the factors controlling fluid migration in the subsurface, pore scale information is necessary. In this study, synchrotron-based X-ray computed microtomography (CMT) is being utilized to extract physically realistic images of carbonate rock cores for the evaluation of porosity and mineralogy in the Mississippian Midale beds of the Weyburn Oilfield in southeastern Saskatchewan. Non-destructive in-situ imaging by CMT is unique as it provides a detailed and novel approach for the description of pore space geometry, while preserving connectivity and spatial variation of pore-body and pore-throat sizes. Here, three-dimensional micron to sub-micron (0.3ìm-100ìm) resolution of CMT is coupled with, and compared against, conventional laboratory-based methods (liquid and gas permeametry, mercury injection porosimetry, electrical resistivity, backscattered electron (BSE) from electron probe micro-analysis (EPMA) and transmitted light microscopy). Petrophysical and mineralogical information obtained from both CMT and conventional methods will have direct implications for understanding the petrophysical mechanisms that control fluid movement in the subsurface of the Weyburn Oilfield.<p>At Weyburn, CO2 gas is being injected into producing horizons to enhance oil recovery and permanently sequester CO2 gas. Fundamental questions exist regarding: (1) The significance of pore geometry and connectivity to the movement of CO2 and other fluids in the subsurface, (2) the nature of the interactions between CO¬2 and pore lining minerals and their impact on petrophysical properties, and (3) the distribution and mineralogy of finely disseminated silicate and carbonate minerals adjacent to pore spaces as interaction among these phases and CO2 may result in permanent sequestration of CO2. <p>The two producing horizons within the Weyburn Reservoir, the Midale Marly and Midale Vuggy units, have variable porosities and permeabilities. Porosity in the Marly unit ranges from 16% to 38% while permeability ranges from 1mD to greater than 150 mD across the field. For the Vuggy unit, porosity ranges from 8% to 21% with permeability ranging from 0.3mD to 500mD. Using CMT, pore space is critically examined to highlight the controlling factors on permeability. Digital processing of CMT data indicates that pore space in the Marly unit is dominated by intercrystalline pores having diameters of approximately 4 ìm. From here, it is noted that the pore-throat radii are approximately ½ the radii of the pore-bodies, having profound implications to current oil recovery methods. Tortuosity values from CMT are also observed to have similar values in three orthogonal directions indicating an isotropic pore space distribution within the Marly unit. Alternatively, the Vuggy unit is found to possess greater pore-body and pore-throat sizes that are heterogeneous in distribution. Based on this, permeability in the Vuggy unit is strongly dependant on pore-length scales that vary drastically between localities.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

Thesis (Ph. D.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references. Also available on the Internet.

The Late Devonian was a significant period in Phanerozoic reef evolution. Reef complexes reached their acme in the Middle Devonian and then declined in numbers and complexity thereafter. This change was accompanied by a shift in reef composition characterized by an increase in calcified microbes in the reef milieu. Late Devonian Nisku Formation reefs in the Cynthia Basin at Meekwap, Alberta are composed of calcimicrobes (Renalcis, Epiphyton, Girvanella, Rothpletzella, and Wetheredella), stromatoporoids, and corals. Accessory organisms include brachiopods, benthic foraminifera, molluscs, sponges, bryozoans, and crinoids. Calcimicrobes generate dorsal or ventral crusts on stromatoporoids, and form oncolites in open marine facies. Dorsal crusts are either Girvanella and Rothpletzella, or non-calcimicrobial, spongiostromate or cemented calcisilt encrustations. Ventral crusts are cryptic and composed of Renalcis and Epiphyton. Oncolites comprise layers of Girvanella and Rothpletzella and occur in lagoon and upper-foreslope facies. Girvanella and Rothpletzella are thought to have been photosynthetic because of their preference for interpreted well-lit settings (oncolites and dorsal surfaces) and possible competition for light as expressed by alternating layers of Girvanella and Rothpletzella as well as domal, accretionary growths of either Girvanella or Rothpletzella in oncolites. Renalcis and Epiphyton are viewed as non-photosynthetic or light sensitive because they are rare on upper surfaces and are instead found in cryptic environments. The abundance of calcimicrobes in Meekwap limestones is interpreted to have reflected elevated nutrient levels. Nutrients were likely terrestrially sourced and brought onto the shelf via fluvial runoff and submarine groundwater discharge. Geometry of the Cynthia Basin, as well as the presence of local nutrient sources at Meekwap is thought to have enhanced more regional nutrification via ocean upwelling. The change in the composition of reefs throughout the Late Devonian is attributed to paleoenvironmental changes, such as a colder climate and falling ocean temperatures, as well as increasing nutrient levels, prior to the Late Devonian mass extinction. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2010-12-21 12:24:17.569

Thesis (M.Sc.)--Memorial University of Newfoundland, 1978. / Includes abstracts in English and French. Typescript. Bibliography: leaves 190-196. Also available online.

Master of Science / Geology / Matthew W. Totten / The Mississippian-aged St. Louis Limestone of Western Kansas is a carbonate resource play that has been producing oil, gas, and natural gas liquids (NGL) for over 50 years. The Mississippian Limestone is made up of heterogeneous limestones with interbedded layers of porous and non-porous units, abrupt facies changes, and diagenetic alterations. These factors combine to characterize the St. Louis Limestone's internal complexity, which complicates hydrocarbon exploration. This study focuses on improving the understanding of the geometry, distribution, and continuity of depositional facies within Kearny County, Kansas. Petrophysical analysis of a suite of geophysical logs integrated with core provided the basis for establishing facies successions, determining vertical stacking patterns within a sequence stratigraphic framework, and correlating areas of high porosity with a respective facies. The following depositional facies were identified; 1) porous ooid grainstone, 2) highly-cemented ooid grainstone, 3) quartz-carbonate grainstone, 4) peloidal grainstone, 5) micritic mudstone, and the 6) skeletal wackestone/packstone. The porous ooid grainstone is the chief reservoir facies, with log-derived porosity measurements between four and eighteen percent. In areas without available core, depositional facies were predicted and modeled using a neural network analysis tool (Kipling2.xla). Values derived from the evaluated core intervals and their respective geophysical logs served as the framework for the neural network model. This study illustrates the advantages of correlating depositional facies with reservoir quality and correlating those specific facies to geophysical logs, ultimately to create a greater understanding of the reservoir quality and potential within the St. Louis Limestone of western Kansas.

This dissertation explores the influence of the environment on the lateral spatial patterning of facies in modern isolated carbonate platforms through six studies. The first study describes the creation of a database of benthic habitat and bathymetric maps derived from multispectral satellite imagery and the field data used calibrate and validate the mapping algorithms. The second study develops and assesses a new approach for remotely-deriving water depth from multispectral satellite imagery without the need for ground-truth information. The third study identifies a criterion for distinguishing between facies belts and mosaics and deploys the criterion to investigate the co-occurrence of these arrangements within modern carbonate depositional systems. The fourth study explores the geologic history of an isolated carbonate platform in the Bahamas, Cay Sal Bank, to understand why the lateral spatial pattering observed in this site differs from the patterns observed in neighboring platforms. The fifth study explores the distribution of carbonate facies in relation to wave energy and water depth for two detached ramps in the Red Sea, Ras Al-Qisbah and Al Wajh. The last study investigates the recovery of scleractinian communities along the coasts of two islands in the Galapagos archipelago, Darwin and Wennman (Wolf) Islands, following a large-scale disturbance in the 1980s. Together, these six studies provide new insight into the spatial patterning of facies within modern carbonate depositional systems and the influence of the environment on the observed arrangements.