CT Analysis Method for Particular Lithology Reservoir Rock
Core analysis is one of the most necessary means to recognize the geological characteristics of reservoirs. Recently, the oil and gas exploration of particular lithology such as volcanic, conglomerate, mud and carbonate rocks continued to make new breakthroughs. As a result, core analysis for particular lithology reservoir rock is increasingly significant. However, conventional methods of core analyzing have great limitations on particular lithology due to the complex chemical components and variable physical status. In order to obtain accurate experimental data and understand the seepage law of particular lithology, advanced core analysis methods are developed through the application of computed tomography (CT). Through the application of nondestructive CT testing for inner construction of core, and the establishing of CT evaluation criterion for the heterogeneity of particular lithology, the goals of analyzing the features and growth of holes and fractures in core and heterogeneity of core are archived. The evaluation criterion is composed by qualitative evaluation and quantitative evaluation, and gives the corresponding evaluation method and formula. The evaluation criterion provides the basis for CT analysis of particular lithology. The application of CT analysis for 211 cores of particular lithology shows: 1) Most conglomerates develops gravel-edge fractures, growth of the fractures is proportional to the level of gravel and inverse proportional to the degree of compaction. Holes in conglomerate are mainly corroding holes between gravel. The growth of holes is related to the composition of cement and compaction. With the lower gravel level, the number of holes and fractures decline. 2) Most volcanic rocks develop holes; some of them develop big holes or lots of holes. Several volcanic samples contain micro-fractures. The growth of holes and fractures in different volcanic rock categories are equivalent, but the type of holes and fractures are different. This research has opened new experimental means for cores of particular lithology. By increasing the skills of core analysis, this research has increased people’s knowledge of reservoir of particular lithology, and means a lot to oil and gas exploration and development.
Riza Esa and Yanwen Wu
Y. Zhou et al., "CT Analysis Method for Particular Lithology Reservoir Rock", Advanced Materials Research, Vols. 301-303, pp. 1372-1377, 2011