Research on dual liquid plugging method based on thixotropic slurry

Aiming at serious leakage problems such as crack type and karst cave type, a dual liquid method is proposed for plugging. Specifically, it is a new type of plugging technology that injects two or more fluids with different properties into the wellbore at the same time, and uses the thixotropy generated by the mixed fluid to seal the lost circulation layer. In order to study the plugging performance of mixed fluid and obtain the best plugging formula,organic gel solution is used to prepare cement slurry indoors, and mixed with Bantu slurry in different proportions. The thixotropy of mixed slurry is measured by hysteresis loop method to evaluate its plugging performance. The results show that when the dosage of organic gel is 0.08% bwoc, the cement slurry prepared by organic gel solution and 0.25% Bantu slurry are mixed at a ratio of 10∶1.8, the slurry has the best plugging performance, and the compressive strength after curing can meet the requirements of on-site construction. Field application shows that the combination of cement slurry prepared with organic gel solution and bentonite slurry has good plugging effect.