Petroleum migration pathways through a basin are determined by the three-dimensional distribution of discontinuous sealing surfaces, which are usually parallel to bedding. The petroleum migrates below the sealing surface taking the structurally most advantageous route. The three-dimensional distribution of migration pathways within the petroleum system can be modelled on a personal computer using a program based on the parameters developed during the research summarised in this thesis. Application of the model to the Paris, Williston, West of Shetlands and Wessex Basins demonstrates that a good correlation can be made between predicted pathways and discovered accumulations using simple models. Migration pathways form a dense network overlying hydrocarbon generating areas in the central parts of basins. Towards the basin margins they commonly become increasingly focused into discrete pathways by the sealing-surface morphologies. The Paris and Williston Basin research showed how relatively minor structuring of geological strata can result in a significant focusing of pathways. Eventually these pathways may reach the surface as shown by seepages. Research in the Wessex Basin revealed that reverse modelling of pathways from seeps assists in the prediction of the location of leaking accumulations. Deflection of the pathways from the structurally most advantageous route below the sealing surface may be caused by lateral sealing barriers due to facies variation in the carrier rock below the seal, fault juxtaposition, or cross-formational seals such as salt intrusions. Deflection of pathways also occurs where there are hydrodynamic conditions in response to topography-driven groundwater flow.

Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains xx, 159 p. : ill. (some col.), map. Includes abstract. Includes bibliographical references (p. 64-65).

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 237-240). Available also in a digital version from Dissertation Abstracts.

Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 180-187). Available also in a digital version from Dissertation Abstracts.

Thesis (Professional Degree)--University of Missouri, School of Mines and Metallurgy, 1930. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed December 15, 2009) Includes index (p. [162-163]).

The sulphate-reducing bacteria (SRB) are a diverse group of organisms which use sulphate as a terminal electron acceptor and produce the highly toxic gas, hydrogen sulphide. The deleterious effects of this include hydrocarbon reservoir souring, formation damage and microbial corrosion. The SRB are of major economic importance to the oil industry. However, knowledge of the microbial ecology of the deep subsurface remains limited. The aim of this project was to investigate whether organisms are indigenous to the hydrocarbon formation and/or are introduced during drilling operations. A range of molecular techniques such as 16S rDNA sequence analysis, probing with labelled oligonucleotides, and denaturing gradient gel electrophoresis (DGGE) were employed to investigate the microbial diversity in oil field samples. A wide range of bacterial 16S rDNA sequences were identified using these molecular methods. An analysis of drilling mud samples revealed a diverse range of bacterial 16S rDNA sequences confirming that bacteria, including SRB, can be introduced to the reservoir during drilling operations. A number of bacterial 16S rDNA sequences were recovered from a geological core sample taken from a depth of 9,770 feet. The microbial diversity was remarkable in such a high temperature, high pressure environment. This lends credence to the theory that certain bacteria may be indigenous to the subsurface environment. Scanning electron micrographs of core which had been incubated in growth medium indicated the presence of 'nannobacteria'. These tiny coccoids, with a diameter of only 0.1 μm are far smaller than the generally accepted minimum size for cellular life forms. The nannobacteria grew in regular colony shaped structures and were seen only in sections taken from inside the rock. This study indicates that hydrocarbon reservoirs provide an environment in which bacteria, if introduced during drill operations, may become established. However, the subsurface also contains complex indigenous microbial populations that demonstrate considerable species diversity and may include unrecognised life forms.

Thesis (M.S.)--West Virginia University, 2004. / Title from document title page. Document formatted into pages; contains xiii, 118 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 71-80).

Thesis (Professional Degree)--University of Missouri, School of Mines and Metallurgy, 1927. / The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed October 12, 2009)

Thesis (Professional Degree)--University of Missouri, School of Mines and Metallurgy, 1922. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed March 17, 2010) Includes bibliographical references (p. 48).

Thesis (M.S.)--West Virginia University, 2005. / Title from document title page. Document formatted into pages; contains xi, 145 p. : ill. (some col.), maps (some col.). Includes abstract. Includes bibliographical references (p. 141-145).