QIU Long-wei1,3*, XU Ning-ning1, ZHOU Yong-yi2, GAO Qing-song2, ZHANG Xiang-jin1, Song Fan1, Ma Xiao-yun1
1. School of Geoscience, China University of Petroleum (Eastern China), Qingdao Shandong 266580, China;
2. Huabei Oil Field of SINOPEC, Zhengzhou 450006, China;
3. Key Laboratory of Basin Analysis and Oil & Gas Reservoir Geology in Universities of Shandong, Qingdao Shandong 266580, China
Abstract: Based on microscopic observations of reservoirs, this paper studied genetic types of pores in Carboniferous-Permian tight sandstone reservoirs in the Daniudi Gasfield, Ordos basin, and investigated their relationships with the genesis of high-quality reservoirs. This study presented observations of the microscopic evidences of reservoir spaces forming directly by the dissolution of detrital quartz grains in tight sandstone reservoirs to demonstrate that characteristics of reservoirs in tight sandstones still closely related with the porosity and dissolution of mineral constituents. The results also showed that 1%~23% of alkaline unstable minerals had been corroded, pores directly from quartz dissolving accounted for more than 60%~90% of the total pores, high-quality reservoirs were favorably formed when the alkaline corrosion were more than 5%, dissolutions of quartz mainly happened in inter-particle-pores near the edges of grains and the damage degree of such formed pores is relatively low during the later continuous compaction since they were formed after strong diagenetic transformation of reservoirs. In summary, this study indicated that corrosion degree of quartz determined the final development process of the reservoir physical property and the formation of high-quality reservoirs.
Keywords: tight sandstone quartz dissolution pores high-quality reservoir formation mechanism Daniudi Gasfield
*Corresponding Author, E-Mail: qiulwsd@163.com
Bulletin of Mineralogy, Petrology and Geochemistry Vol. 34, No.1, 2015, page 38-44
