The kaolinite cementation and reservoir assessment of the Upper Triassic Chang-2 pay set in the Jiyuan region,Shaanxi

The secondary pores accounts for a greater proportion almost 50% of reservoir sandstones in the Chang-2 pay set in the Jiyuan region.The diagenesis may exercise a major control on the development of oil reservoir spaces.The concentration of kaolinite in the Jiyuan region in the south-central part of the Ordos Basin implies that stronger meteoric water action resulted in the dissolution of aluminosilicates and cementation of kaolinite in the Jiyuan region than in the other parts of northern Shaanxi.The integration of the content and distribution of kaolinite,sedimentary facies belts and structural highs led us to delineate eight relative favourable areas for further assessment of hydrocarbon accumulation in the Jiyuan region.