鄂尔多斯盆地西峰油田合水地区庄31井区储层岩性主要为长石质岩屑砂岩和长石岩屑质石英砂岩。孔隙类型为粒间孔和长石溶孔,孔径一般10～40μm。产层平均孔隙度9.5%,平均渗透率0.25 mD,属典型的低渗透特征。通过美国岩心公司经验统计法、含油产状法、测试法确定了研究区有效储层物性下限,孔隙度为7%,渗透率为0.06 mD,为有效厚度划分及储量计算提供了依据。 The reservoir lithology of Zhuang-31 well in Heshui area, Xifeng Oilfield, Ordos Basin is mainly feldspathic lithic sandstone and feldspathic quartzite sandstone. Pore ​​types of intergranular pores and feldspar dissolved pores, pore size is generally 10 ~ 40μm. The average porosity of the formation is 9.5% with an average permeability of 0.25 mD, which is typical of low permeability. Through the experience of American core company statistic method, oil producing method and test method, the lower limit of effective reservoir property is determined. The porosity is 7% and the permeability is 0.06 mD, which provides the basis for effective thickness division and reserves calculation.