Abstract:

Clay minerals consist mainly of kaolinite and randomly interstratified illite/montmorillonites(S/I) in the clastic reservoir in Shahejie Formation in the Zhengjia-Wangzhuang area in DongYing sag according to thin section, X-ray diffraction, infrared ray spectrum analyses. Still, illite and chlorite exist in a small amount. The results of the study show that S/I can the subdivided into three kinds: calcium type, natrium type and their mixture type, of which the natrium one has the worst influence on reservoirIn this area, the high crystallinity kaolinite is the most, and its most possible origin is authigenic. The low crystallinity kaolinite is allogenic or from feldspar's alteration. And authigenic kaolinite can improve the reservoir physics effectively.

Key words: randomly interstratified illite/montmorillonites, kaolinite, clastic reservoir, formation damage