Research On Reservoir Characteristics And Oil-controlling Of Chang 2 And Chang 6 Formation In Yanhewan Block Of Ordos Basin

Yanhewan Oil field is located in the middle part of Yishan slope of ordos Basin,belongs to the up-producing area of Yanchang petroleum company.The reservior of study area is mainly composed of Chang 2 and Chang 6 group in Triassic Yanchang Formation. On the basis of observation and analysis of rock sections, cast sections, ESM and mercury injection curves,the reservior rocks of Chang 2 and Chang6 are mainly composed of fine lithic arkose with good physical conditions. The main pore types in the reservoir are as follows:primary intergranular pore, laumontite-intergranular pore and feldspar dissolution pore.The Chang 2 reservior of study area mainly belongs to the I type reservior,which of good reservoir property; and the Chang 6 reservior mainly belongs to the IV type reservior with poor reservoir property, it has dense lithology.The Chang 2 and Chang 6 reservior,belongs to branch channel of plant and front delta deposit. Oil-gas is mainly distributed in branch channel and point bar, with Northeast to Southwest strip spreading. The major controlling factors of hydrocarbon accumulation is Lithology, Tectonic and Occlusion. Chang 2 oil reservior is far-source accumulating and reservoir-forming,and Chang 6 oil reservior is near-source accumulating and reservoir-forming. Based on the deep research on the characteristics and the control factors of hydrocarbons, then showing definite direction of exploration and development in future.