Tübingen, Universiẗat, Diss., 2001.

The Middle East has 62% of the world’s proved conventional oil reserves; more than 70% of these reserves are in carbonate reservoirs. It also has 40% of the world’s proved conventional gas reserves; 90% of these reserves are hold in carbonate reservoirs. Recently papers published from industry discussed the techniques, planning, and optimization of acid stimulation for Qatar carbonate. To the best of author’s knowledge, no study has focused on the acid reaction to Qatar carbonates. The lack of understanding of Qatar carbonate especially Middle East carbonates and the abundance of Middle East carbonate reservoirs is the main motivation behind this study. This work is an experimental study to understand the acid response to Qatar rocks in rocks with two types: homogenous carbonate and heterogeneous carbonate. A large portion of this research is to further investigate the impact of centimeter scale heterogeneity on the acid stimulation using Qatar rocks. Qatar carbonates have multi-scale heterogeneities which may cause the impact of the injected acids to differ from homogenous case. Recent published field data indicate a much smaller number of pore volume to breakthrough compared with experimental measurement with homogeneous carbonate and heterogeneity is believed to be one of the contributors of causing the low field measurements. In this case, acid linear core-flood experiments were conducted with carbonate core samples of different petrophysical properties to study the impact of both separated and connected vugs and channels on pore volume to breakthrough. Computerized tomography was used in characterization of the heterogeneities. One experiment simulated the response of acid to heterogeneous carbonate in downhole condition with drill-in fluid damage. Homogeneous rock was cored from a well in Qatar. The optimal injection rate was pursued through acid core flood experiments for acid stimulation design and for further reference. It is been discovered that the optimum injection rate for heterogeneous carbonate exists. For the similar acid flux, the corresponding PVBT for buggy limestone correlates inversely with the fraction of total porosity comprised by vugs. For vuggy carbonates with connected vugs and channels, whether or not formation damage exists, the acid tends to create new pore space nearby to the existing vugs and channels. Different strategies need to be made regarding acid stimulation design with homogeneous carbonate, heterogeneous carbonate with separated vugs and channels and heterogeneous carbonate with connected vugs and channels.

Thesis (Ph. D.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on Mar. 18, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Geophysics, Department of Physics, University of Alberta. Includes bibliographical references.

The determination of reservoir quality and its spatial distribution is a key objective in reservoir characterization. This is especially challenging for carbonates because, due to the effects of diagenesis, quality rarely follows depositional patterns. This study integrates data from thin sections and core analyses with measurements of Nuclear Magnetic Resonance (NMR) T2 relaxation times. It exposes a novel approach to the use of NMR by applying geological and statistical analysis to define relationships between pore characteristics and the T2 data, from which a method to identify pore origin from NMR only is developed. One hundred and three samples taken from eleven wells located in fields of the Middle East, Alabama and Texas were used in the study. Modeling of the T2 spectra, as the sum of three normal components, resulted in the definition of 9 parameters representing the average, the variability and the percentage of total porosity of the specific pore sizes present in the sample. Each specific pore size corresponds to one of the following genetic pore types: intergranular, matrix, dissolution-enhanced, intercrystalline, vuggy and cement-reduced. Among the 9 parameters, two variables were identified as having the highest degree of geological significance that could be used to discriminate between pore categories: µmax which represents the largest average pore size of all pore types identified in the sample, and σmain which represents the size variability of the most abundant pore type. Based on the joint distribution of µmax and σmain computed for each pore category, the probability that an unclassified sample belongs to each of the pore categories, is calculated and the sample is assigned to the category with the highest probability. The accuracy of the method was investigated by comparing NMR predicted pore origin and genetic pore type described from thin section. A result of 89 successful predictions out of 103 samples was obtained. These promising results indicate that T2 time can be a useful identifier of carbonate pore types. Success in this work takes us closer to identifying genetic pore types from NMR logs with minimal calibration against borehole cores and will help predict the spatial distribution of poroperm facies in complex carbonate reservoirs with much improved accuracy.

No description available.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1927. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

An investigation of minor elements distribution in sedimentary and metamorphic carbonates was made. A copper oxide D. C. Arc Technique of spectrographic analysis was developed for determination of minor elements in carbonates. Forty-five samples of carbonates extracted from Paleozoic limestones of Alberta and Ontario, Precambrian marbles of Ontario and from Grenville Lens and Vein Carbonates of Ontario and Quebec were analyzed, and the concentrations of Mg, Mn, Fe, Sr, Ba, Pb, Al, Si, Ti, B, Cr, and Ni were determined. The structure and some chemical properties of carbonates were discussed. An attempt to locate the minor elements in the crystal structure was made. / Thesis / Master of Science (MS)

Thesis (Ph. D.)--University of Wisconsin--Madison, 1928. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 97).

Typescript. / Thesis (Ph. D.)--University of Hawaii at Manoa, 1984. / Bibliography: leaves 219-236. / Microfiche. / xviii, 236 leaves, bound ill. 29 cm

Presented as Thesis (Ph. D.)--University of Wisconsin--Madison, 1917. / Cover title. Reprinted from Journal of agricultural research, vol. XII, no. 8 (25 Feb. 1918). Includes bibliographical references (p. 500-504).