合水地区长6油层微观渗流特征及驱油效率影响因素研究

对鄂尔多斯盆地合水地区长6油层组超低渗透储层的微观渗流特征及驱油效率影响因素进行深入研究,为提高采收率提供了科学依据。研究以真实砂岩微观模型渗流实验为主要手段,结合铸体薄片、扫描电镜、压汞等方法对孔隙结构、岩石类型等进行测试。研究表明,研究区长6油层的渗流特征以网状驱替和均匀驱替为主,指状驱替甚少;不同的驱替类型对应不同的最终驱油效率,均匀驱替模型最终驱油效率最高,指状驱替模型最低。储层物性中渗透率是影响驱油效率的主要因素,孔隙度次之;适当地提高驱替压力能够有效地提高驱油效率;提高注水体积倍数也能适当地提高驱油效率;非均质性对驱油效率也有一定的影响。

Micro-flow characteristics and influencing factors of oil displacement efficiency of Chang-6 reservoir in Heshui area

The present paper is aim at a deeper study on the micro-seepage flow and the influencing factors of displacement efficiency of Chang6 reservoir of Triassic Yanchang Formation in the area of Heshui,in the Ordos Basin in order to provide a scientific basis for increasing the recovery ratio.Take the real sandstone micro-model experiment as the main method in this study,and combined with the checkup of slices,SEM,mercury penetration etc.to study the pore structure,the composition of the rocks.The results show that the water-drive patterns in the reservoirs of Chang6 in this area are mainly homogeneous seepage and reticular seepage,the finger like seepage is few.The homogeneous seepage gets the highest final oil saturation and final displacement efficiency,the models of reticular seepage are lower,the models of the finger like seepage are the lowest.As to the physical properties,the permeability is the first factor affecting the displacement efficiency,the porosity is the second;the displacement efficiency can be increased effectively by increasing the drive pressure advisably;the displacement efficiency also can be increased by increasing the multiple volume of driving water,finally the heterogeneity also is one of the affecting factors.