LI Ting-ting1, ZHU Ru-kai1,2*, BAI Bin1,2, WANG Chong-xiao3, LI Tie-feng3
1. Research Institute of Petroleum Exploration & Development, PetroChina, Beijing 100083, China;
2. State Key Laboratory of Enhanced Oil Recovery, Beijing 100083, China;
3. Research Institute of Petroleum Exploration & Development, PetroChina, Yumen Oilfield Company, Yumen Gansu 735200, China
Abstract: Study on pore-throat characteristics is one important part of reservoir assessment. Studying pore-throat features in different lithologies has great significance in reservoir study. On basis of thin-section observation and X-ray diffraction analysis, field-emission electron microscope observation, Qemscan system and mercury injection analysis, dolomite-bearing mudstone and argillaceous dolomite of the lower Cretaceous reservoir in the Qingxi depression were analyzed. The results indicated that the dolomite-bearing mudstone consists high contents of clay minerals, develops clay-mineral interlayered pores and contains some pyrite intercrystalline pores and microfractures with few intraparticle pores, in which micrometer-scale pores (diameter: 10-200 μm) are dominant. The Argillaceous dolomite mainly develops grain-edge fractures, interparticle pores, microfractures and organic matter contracted fractures, occasionally contains organic matter dissolved pores and pyrite intercrystalline pores, many of which are nanometer-scale pores, with diameters of 20-200 nm. Preliminary study had been conducted on the differences of pore-throat characteristics of the two lithologies and the results indicated the main controlling factors are mineral composition, compaction and the maturity of organic matter
Keywords: dolomite-bearing mudstone argillaceous dolomite pores microfractures
*Corresponding Author, E-Mail: zrk@petrochina.com.cn
Bulletin of Mineralogy, Petrology and Geochemistry Vol. 34, No.1, 2015, page 79-85
