低渗透油层弱水湿岩心的合理驱替速度

The reasonable displacement rate of the weakly water-wet cores for low permeability oil layers

为探索考虑动润湿滞后条件下低渗透油层弱水湿岩心的合理驱替速度,将岩石孔隙简化为等直径平行毛管束,通过压力平衡方程式,建立驱替速度、接触角以及渗透率等之间的理论关系式,进行低渗透油层弱水湿岩心水驱油实验研究,利用实验数据求出理论关系式中的有关参数,并在Moore和Slobod毛管数定义式的基础上,对毛管数进行适当的修正.结果表明:低渗透油层弱水湿人造岩心接触角为79.032°时,其水驱采收率最高为47.67%;合理驱替速度与渗透率之间符合二次曲线关系,当岩心渗透率为50×10-3μm2时,合理驱替速度为1.4 m/d.

In order to explore the reasonable displacement rate of the weakly water-wet cores for low permeability oil layers in the condition of dynamic wettability hysteresis,the core is simplified to be a parallel capillary bundle to establish theory relational expression between the displacement rate,contact angle and permeability through the pressure balance equation.We conducted the experimental study of water displacing oil of the weakly water-wet cores for low permeability oil layers and obtained the relevant theoretical parameters by the experimental data.The appropriate amendments were carried out for capillary number based on Moore and Slobod definition.The results show that: the weakly water-wet cores for low permeability oil layers have the maximal water flooding oil recovery which is 47.67% when contact angle is respectively 79.032°;the reasonable displacement rate and permeability are founded by the second curve.The reasonable displacement rate is 1.4 m/d when the permeability of the core is about 50×10-3 μm2.