No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
Controls on the distribution, source and timing of mineral cements in an oilfield.
Abstract
Thesis (Ph. D.)--Queen's University of Belfast, 1999.
... There has to be a`sink' for the remaining K in solution after the precipitation of illite. Analysis of the adjacent LKCF and UKCF using quantitative XRD (Barclay, 1999) demonstrated that the major clay mineral in the LKCF and UKCF is illite (where the illite is broadly the same as muscovite in composition, McHardy et al., 1982). It has been suggested that one of the major pre-burial clay minerals present in the LKCF and UKCF mudrocks was mixed-layer smectite-illite (Scotchman, 1987;Shaw & Primmer, 1991). ...
... where AQ, AI, AK and AA are the vol.% of authigenic quartz, illite, kaolinite and ankerite, respectively. These data have been estimated from modal analyses of thin sections (Barclay, 1999). This calculation produced an average KFD of 14 vol.% ...
A reaction path model was constructed in a bid to simulate diagenesis in the Magnus Sandstone, an Upper Jurassic turbidite reservoir in the Northern North Sea, UKCS. The model, involving a flux of source rock-derived CO2 into an arkosic sandstone, successfully reproduced simultaneous dissolution of detrital K-feldspar and growth of authigenic quartz, ankerite and illite. Generation of CO2 occurred before and during the main phase of oil generation linking source rock maturation with patterns of diagenesis in arkosic sandstones and limiting this type of diagenesis to the earlier stages of oil charging. Independent corroborative evidence for the model is provided by formation water geochemical data, carbon isotope data from ankerite and produced gas phase CO2 and the presence of petroleum inclusions within the mineral cements. The model involves a closed system with respect to relatively insoluble species such as SiO2 and Al2O3 but is an open system with respect to CO2. There are up to seven possible rate-controlling steps including: influx of CO2, dissolution of K-feldspar, precipitation of quartz, ankerite and illite, diffusive transport of SiO2 and Al2O3 from the site of dissolution to the site of precipitation and possibly the rate of influx of Mg2+ and Ca2+. Given the large number of possible controls, and contrary to modern popular belief, the rate of quartz precipitation is thus not always rate limiting.
ResearchGate has not been able to resolve any references for this publication.