Master of Science (MS)
Geology and Geophysics
A microfacies based approach is proposed for the petrophysical prediction of the most effective hydrocarbon seals. Four distinct microfacies types deposited by different deep water depositional processes have been identified based on textural and mineralogical characteristics. Individual microfacies types include: 1) finely laminated, silt poor to slightly silty hemipelagic claystones; 2) faintly laminated, slightly to moderately silty distal hemiturbiditic claystones; 3) weakly laminated, moderately silty to slightly sandy intermediate hemiturbiditic mudstones; and 4) very silty and sandy proximal hemiturbiditic mudstones. Hemipelagic and distal hemiturbiditic claystones (microfacies types 1 and 2) containing well to modestly organized fabric, high total clay contents, and low abundances of detrital silt are the most effective hydrocarbon seals. Intermediate and proximal hemiturbiditic mudstones (microfacies types 3 and 4) generally display a lack of fabric orientation and contain increased amounts of silt and sand that experience grain to grain interaction, resulting in the preservation of larger pore throat diameters and consequently lowered seal qualities. Descriptive statistical analysis has differentiated microfacies types 1 and 2 from their coarser grained counterparts as having higher mean bulk densities, natural gamma ray, total volume of shale, and total volume of clay readings. Discriminant statistical procedures including single decision tree and random forest analysis have predicted select mineralogical and petrophysical variables for the empirical classification of individual microfacies types.
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Mbamalu, Nchekwube, "Evaluation of microfacies controls on hydrocarbon seal quality" (2010). LSU Master's Theses. 444.