Pore Structure Characteristics and Evaluation of the Yanchang Formation Chang 6 Reservoir in Ansai West Area

Based on the analysis of the core observation,rock and mineral slices,cast slices and SEM,the results show that Chang6 reservoir is mainly of fine feldspar sandstone,following are medium-fine grained,medium grained,silt-fine grained,and silt arcose.The dominating pore space of Chang6 reservoir includes intergranular pores,the dissolved pore in the laumontite,intergranular dissolution pores(feldspar,cutting),the main pore combination types include dissolved pore-intergranular pores,intergranular pores,microporous and compound,etc.The characteristic parameters of pore-throat of Chang6 change greatly,pore-throat distributes unevenness,and medium pore-fine throat and low pore-microthroat are main types.