弱碱三元复合驱对储层的损害研究

Study on reservoir damage by alkalescence-surfactant-polymer flooding

弱碱三元复合驱过程中,碱的存在容易对储层产生损害,通过比较不同碱浓度的单一碱体系和弱碱三元复合体系与储层的相互作用,研究了弱碱三元复合驱过程中生成的碳酸盐垢、硅垢和黏土膨胀对储层的损害。结果表明,与弱碱三元复合体系反应后的钙镁离子浓度和硅离子浓度均低于单一碱体系,碳酸盐垢和硅垢的形成趋势弱于单一碱体系,结垢对储层的伤害较小。黏土矿物在弱碱三元复合体系中的视膨胀率稍大于单一碱体系中的黏土矿物的视膨胀率,但由于黏土矿物在岩石成分中所占比例较小,黏土膨胀对储层的损害也较小。

The presence of alkalescence is harmful to reservoir during the alkalescence-surfactant-polymer（ ASP）flooding. Through comparing the interactions of the single alkalescent systems and ASP with the reservoir under different alkine concentration,the reservoir damages by carbonate scale,silicon scale and clay swelling during ASP flooding are studied. The results show that the concentrations of Ca2 ＋,Mg2 ＋and Si4 ＋in ASP system are all lower than that in single alkalescent systems. Meanwhile,the formation probability of carbonate scale and silicon scale is less than that in single alkalescent systems,indicating that the scales in ASP flooding exert less damage to reservoir. Apparent swelling ratio of clay in ASP systems is slightly higher than that in single alkalescent systems,however,it also presents less damage to reservoir due to the small proportion of clay in rock.