Significance of stylolite on organic matter enrichment and fluid migration: A case study on stylolite in the Ordovician carbonate rocks of Ordos Basin
GAO Gang, WANG Xuan, ZHANG Weiwei, DONG Yan, WANG Chengcheng, LI Jiaye
1 State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum-Beijing, Beijing 102249, China 2 Exploration & Development Institute, Xinjiang Oil Field Company, PetroChina, Karamay, 834000, China
In this paper, Ordovician stylolite-bearing marine carbonate rock samples in the eastern-middle part of the Ordos Basin were selected and analyzed. A series of analytical experiments such as observation of casting thin section and fluorescent thin section, TOC test, Rock-Eval pyrolysis, X-ray diffraction of whole rock, and scanning electron microscopy were conducted to analyze the effect of stylolites in carbonate rocks on organic matter enrichment and hydrocarbon migration. It is indicated in the study that the stylolites represent higher TOC content and better oil-bearing properties than that of the neighboring matrix; however, the two contain similar kerogen type. The stylolite contains a relatively higher content of clay, quartz, dolomite, pyrite, and black bitumen; but relatively lower content of calcite. The grains in the stylolite generally represent basal cementation and matrix supported features. The pore developmental degree, pore types, and pore developmental density are better than that of the matrix, favoring the migration of hydrocarbon. In general, the stylolite demonstrates a positive effect on the organic matter enrichment, hydrocarbon generation, and fluid in carbonate rock with low organic matter abundance.
高岗,王轩,张维维,董岩,王程程,李佳烨. 缝合线有机质富集及流体运移意义——以鄂尔多斯盆地奥陶系碳酸盐岩为例[J]. 石油科学通报, 2017, 2(1): 1-11. GAO Gang, WANG Xuan, ZHANG Weiwei, DONG Yan, WANG Chengcheng, LI Jiaye. Significance of stylolite on organic matter enrichment and fluid migration: A case study on stylolite in the Ordovician carbonate rocks of Ordos Basin. Petroleum Science Bulletin, 2017, 2(1): 1-11.