核磁共振方法在致密砂岩储层孔隙结构中的应用--以鄂尔多斯大牛地气田上古生界石盒子组3段为例

采用低场核磁共振实验的方法研究了鄂尔多斯盆地大牛地气田上古生界石盒子组3段岩芯样品的核磁共振弛豫时间T2分布与由压汞毛管压力曲线所获得的孔喉半径分布之间的对应关系和转换方法,建立了T2几何平均值与毛管压力曲线孔喉结构参数之间的统计关系.研究结果表明,致密砂岩储层的核磁共振T2分布与由毛管压力曲线所获得的孔径分布之间存在密切的相关性,二者都反映了岩石的孔隙结构,利用核磁共振技术来评价致密砂岩储层的孔喉结构是有效的,同时也为利用核磁共振测井技术开展致密砂岩储层评价提供了实验基础.

Application of Nuclear Magnetic Resonance Technology to Pore Structure in Tight Sandstone:A Case from Third Member of Shihezi Formation Upper Paleozoic in Daniudi Gas Field,Ordos Basin

By using low field nuclear magnetic resonance core analysis methodology,this paper describes the correlation and transition method between T_2 distribution from nuclear magnetic resonance(NMR) experiment in lab and pore throat radius distribution from capillary pressure data from third member of Shihezi Formation of Upper Paleozoic in Daniudi Gas Field,Ordos Basin.Accordingly,it has set up the statistical relations between T_2 geometrical average value and parameters of pore throat structure from capillary pressure data.Meanwhile, it reveals that there has been close relation between T_2 distribution from NMR experiment in lab and pore distribution.It is shown by experiment results that it is available to use NMR technology to evaluate pore structure of tight sandstone reservoir.