The Effect of Thixotropic Additive on Cement Slurry Properties to Overcome Lost Circulation

Abstract

Lost circulation during drilling operations presents significant challenges, potentially leading to financial losses, extended non-productive time, environmental hazards, and safety risks. Addressing this issue requires plugging slurries that effectively seal off loss zones within the drilled formation. One promising approach involves the incorporation of thixotropic additives into cement slurries, which exhibit fast gelling properties when static, thereby forming plugs to mitigate lost circulation. The research results aim to determine the effect of adding thixotropic additives on cement slurry properties and to find concentration limitations of thixotropic additives in cement slurry design. The cement slurries containing thixotropic additives will exhibit superior rheology and gel strength compared to those without additives. The second effect of adding thixotropic is faster hardening of cement slurry and decreased strength of cement. Based on the percentage of the weight of cement, this research found that the optimal concentration of thixotropic additive is 0.10%, with a mixing time of 40 seconds. Rheological readings and gel strength, both at room temperature and circulating temperature, are still quite good. Using of 0.15% thixotropic additive is the maximum limit that can be recommended but with certain notes (mixing time is too long). The use of thixotropic additive 0.15% has a mixing time of 1 min 40 sec, whereas for laboratory scale, mixing with a time range > 1 min cannot be recommended because it is too long. From the mixing time, we can also find out the condition of the cement slurry, which is thick and difficult to mix.