旬邑-宜君区块长3段孔隙结构特征及其在储层评价中的应用

低渗透储层微观孔隙结构是储层研究的重点与难点,直接影响储层评价的准确性。以鄂尔多斯盆地旬邑-宜君区块延长组长3段低渗透储层为例,在薄片观察、岩石孔渗、压汞测试与测井资料分析基础上,研究储层微观孔隙结构类型及特征,将储层分为4种孔隙结构类型,阐述各类储层的储集空间类型、孔渗特征、毛管压力曲线特征差异,Ⅰ类和Ⅱ类储层为研究区有利储层;选用储层品质系数与储层微观孔隙结构特征参数(排驱压力、平均孔喉半径和分选系数),对储层进行评价;WB44等4口井评价结果表明,储层孔隙结构类型影响低渗透储层的产能评价和测井解释。

Pore structure characteristics of Chang-3 member in Xunyi-Yijun block and its application in reservoir evaluation

The study on microscopic pore structure is not easy and it plays an important role in low permeability reservoir research,which directly affects the accuracy of reservoir evaluation.By taking low permeability reservoirs of Chang-3member from Yanchang formation in Xunyi- Yijun area,Ordos Basin as the example,based on the study of thin sections,rock porosity and permeability,capillary pressure test and well log analysis,the study on reservoir microscopic pore structure types and characteristics has been carried out and therefore,the reservoir is divided into four kinds of pore structure.The aspects of reservoir space types,porosity and permeability characteristics,capillary pressure curve characteristic differences have been fully clarified.Type-I and type-II reservoirs are considered to be favorable,the reservoir quality index and reservoir microscopic pore structure characteristics parameters(displacement pressure,average pore throat radius and sorting coefficient)have been chosen to make reservoir evaluation. The evaluation results of WB44 and other 4 wells indicate the pore structure type has a direct effect on capacity evaluation and log interpretation of low permeability reservoir.