低渗砂岩与微裂缝泥灰岩储集层毛细管压力曲线特征对比

摘要

Usually,capillary pressure curve of sandstone is a smooth curve.However,the curve of marlstone with micro-fractures consists of two parts： an oblique line and a flat one.So the parameters such as threshold pressure and mean throat radius gained from capillary pressure curves of marlstone cannot describe the pore structure properly.This paper mainly discusses and analyzes the difference of mercury injection curves between sandstone and marlstone,and proposes a concept of effective throat radius to describe the pore structure of marlstone with micro-fracture.The case study shows this method is better than before.%一般砂岩的毛细管压力曲线为一圆滑曲线,而具有微裂缝的泥灰岩毛细管压力曲线由斜线段和平坦段两部分组成。根据毛细管压力曲线求取的排驱压力、平均孔喉半径等参数无法真实反映泥灰岩的孔隙结构特征。因此就低渗砂岩储集层和具微裂缝的泥灰岩储集层的岩石毛细管压力曲线进行对比分析,并提出有效孔喉半径的概念来描述微裂缝泥灰岩的孔隙结构特征。结果表明,此方法能较好地反映微裂缝泥灰岩储集层的孔隙结构特征。