致密砂岩双重介质储层可动流体影响因素分析——以鄂尔多斯盆地泾河长8段为例

致密砂岩双重介质储层的孔喉细小,裂缝发育,流体赋存状态不同于常规储层,可动流体参数是评价该类储层开发潜力的重要参数。利用核磁共振技术,结合恒速压汞分析等手段,对鄂尔多斯盆地南缘泾河油田长8段致密砂岩双重介质储层的可动流体特征及主要影响因素进行了分析,结果表明,泾河油田长8段储层存在5种典型的T2谱曲线形态,储层可动流体平均饱和度为44.8%,可动流体平均孔隙度为2.9%;储层孔道半径为90~180μm,喉道半径为0.1~0.8μm;水平层理缝密度为5.01~64.80条/米,平均21.10条/米。泾河油田长8段储层具有低可动流体饱和度和低可动流体孔隙度的特征;储层宏观物性与可动流体参数相关性越强,物性越好,可动流体饱和度越高;主流喉道半径和层理缝密度是控制致密砂岩双重介质储层可动流体饱和度的主要因素。

Influencing factors analysis of movable fluid in dualporosity tight sandstone reservoir: A case study from Chang 8 formation in Jinghe oilfield of Ordos basin

The dual-porosity tight sandstone reservoir has the characteristics of small pore throat and developed fractures,and the fluid occurrence status is different from that of the conventional reservoirs.The dynamic fluid parameter is an important parameter to evaluate the development potential of this kind of reservoirs.By using the nuclear magnetic resonance experiment,combining with the constant speed mercury injection,the movable fluid characteristics and main influencing factors of dualporosity tight sandstone reservoir of Chang 8 formation of Jinghe oilfield in south of Ordos basin were studied.The results show there are 5 typical T2 spectral curves in Chang 8 formation of Jinghe oilfield,the mean saturation of the movable fluid in reservoir is 44.8,the mean porosity of the movable fluid is 2.9%,the pore radius is 90~180μm,and the radius of the throat is 0.1~0.8μm,the horizontal seam density is 5.01~64.8/m,and the average is 21.1/m.Therefore,Chang 8 formation of Jinghe oilfield has the characteristics of low movable fluid percentage and low movable fluid porosity.The macroscopical properties of reservoir are strongly correlated with dynamic fluid parameters,and the better the property,the higher the fluid content.The main factors that control the fluid content of the dual-porosity tight sandstone reservoirs are the mainstream throat radius and the seam density.