鄂尔多斯盆地延长气田Y113—Y133天然气井区盒8段致密储层物性下限

The lower limit of physical properties of tight reservoir in He 8 Member of Y113-Y133 gas well area,Yanchang Gas Field,Ordos Basin

阐明鄂尔多斯盆地延长气田盒8段致密储层物性下限及分布,可为延长气田致密砂岩气勘探开发提供理论依据。综合应用岩心、测井以及试气等资料,对鄂尔多斯盆地延长气田Y113—Y133天然气井区盒8段致密储层物性下限进行研究。结果表明:研究区盒8段主要为岩屑砂岩,填隙物主要为水云母和硅质,孔隙类型有原生孔隙和次生孔隙,后者居多;综合利用经验统计法、压汞法以及试气法进行研究,并通过建立物性模型、最大孔喉半径与物性拟合以及生产动态资料检验,最终认为盒8段致密储层孔隙度下限为5%,渗透率下限为0.06×10^(-3)μm^(2),对应的排驱压力为1.7 MPa,中值压力为20 MPa,最大孔喉半径为300 nm;在此基础上将有效储层分为3类:Ⅰ类储层物性、含气性等最好,是最有利储层,位于河道中心位置;Ⅱ类储层较好,分布于河道较中心位置;Ⅲ类储层最差,位于河道边缘位置。

The lower limit of physical property and distribution of tight reservoir in the 8th Member of Permian Shihezi Formation(He 8 Member)of Yanchang Gas Field in Ordos Basin are clarified,which can provide theoretical basis for tight gas exploration and development in Yanchang Gas Field.The lower limit of physical properties of tight reservoir in He 8 Member of Y113-Y133 gas well area in Yanchang Gas Field,Ordos Basin was studied by comprehensive application of core,logging and gas test data.The results show that He 8 Member in the study area is mainly lithic sandstone,the interstitial materials are mainly hydromica and siliceous,and the types of pores are primary pores and secondary pores,with the latter predominating.Comprehensive use of empirical statistics,mercury injection method and gas test method,and through the establishment of physical property model,maximum pore-throat radius and physical property fitting and production dynamic data inspection,the lower limit of physical property of He 8 tight reservoir is determined as follows:The porosity is 5% and the permeability is 0.06×10^(-3)μm^(2),corresponding displacement pressure is 1.7 MPa,median pressure is 20 MPa,and maximum pore throat radius is 300 nm.On this basis,the effective reservoir can be divided into three types:Type Ⅰ reservoir with the best physical and gas-bearing properties is the most favorable reservoir located in the center of the channel,Type Ⅱ reservoir is the best reservoir,and Type Ⅲ reservoir is the worst reservoir located at the edge of the channel.