Reservoir Characters of Classic Rocs of the Shanxi Formation at Yi-Meng Area,Northern of Ordos Basin

Key words: 
• Yi-Meng area /
• Shanxi Formation /
• classic rocks reservoir /
• micro-facies and micro-physical property /
• controlling factor /

Abstract: sandy-conglomerated braided channel of middle fan, the point-sandbar deposit ofmeandering river and the distributor channel sand of the delta-plain are the main sandstone reservoir of the shanxi formation at the Yi-Meng area. The sand bodies are consisted of quartz sandstone and lithic sandstone with abundant impurity and lithic fragment. It is characterized by the low porosity,low permeability,the heterogeneities and secondary pores predominantly. Their physical property are associated with its depositional micro-facies:the physical property of the point-sandbar deposit,the distributor channel deposit and sandy-conglomerated braided channel gradually become worse and worse. Based on the relationship between pore-throat types,the shanxi formation sandstone reservoir could be classified into four types. Tl}e reservoir of middle porosity and low permeability with solution pore and remainder intergranular porosity is distributed of the point-sandbar deposit and the distributor channel deposit are mainly objective formations of exploration in South Yi-Meng;The reservoir of low porosity and low permeability with intercrystal pore is distributed of the sandy-conglomerated braided channel and can consisted of the lithologic reservoir with tectonic setting;The compacted reservoir with micro-pore and micro-fracture scarcely are discovered oil and gas in the area;The exceed compacted reservoir with no pore and fracture are not discovered oil and gas in the area.