孔喉尺度弹性微球调驱影响因素

Study of influencing factors on pore-scale elastic microspheres flooding

为了进一步表征孔喉尺度弹性微球的调驱效果,通过填砂管驱替实验,研究了微球粒径与岩心孔喉直径之比、驱替速度、微球质量浓度对调驱效果的影响。结果表明:微球封堵率和最大变形运移压力梯度随微球粒径与孔喉直径之比的增加先增大后减小,随驱替速度的增加而减小,随注入微球质量浓度的增加而增大。当微球粒径与孔喉直径之比为1.4～1.5时,调驱效果较好;当微球粒径与孔喉直径之比为1.42时,微球封堵率和最大变形运移压力梯度均达到最大,分别为90.4%和0.1MPa/m;当驱替速度大于5m/d时,驱替速度对微球封堵率和最大变形运移压力梯度的影响变小。在矿场条件下,近井地带驱替速度大,远井地带驱替速度小,微球可以顺利运移至远井地带,到达油藏深部并形成有效封堵,实现深部调驱。当微球质量浓度大于1500mg/L后,随微球质量浓度增加,封堵率的增加幅度变小。

The effect of the ratio of microsphere size to pore-throat diameter,displacement rate and concentration of microspheres to the microspheres profile control and flooding are estimated through sand pack displacement experiment in this paper.The results show that,as the ratio of microsphere size to pore-throat diameter increased,the plugging rate and the maximum deforming migration pressure gradient increases first and then decreased.When the displacement rate decreased or the concentration of microspheres increases,the plugging rate and the maximum deforming migration pressure gradient increase accordingly.The optimized ratio of microsphere size to pore-throat diameter is between 1.4 and 1.5;the largest plugging rate and the maximum deforming migration pressure gradient are achieved,which are 90.4 and 0.1 MPa/m,under condition that the ratio is 1.42.The effect of displacement rate to plugging rate and the maximum deforming migration pressure gradient becomes weak,if the displacement rate is larger than 5 m/d.On field conditions,the displacement rate of near borehole zones is high,which is small in the place far from the borehole,so,the microspheres are able to migrate into the deep reservoir and plug the formation.When the microspheresconcentration is greater than 1 500 mg/L,as the concentration increasing,the increasing rate of plugging rate decreases.