Performance Evaluation on Over-Saturated Brine Cement Slurry of Anhydrite Formation

摘要

The anhydrite formation has a highly negative impact on the stability of cement slurry, which can cause failure of cementing operation upon well construction. In combination to anhydrite characteristics of Missan Oilfields, herein, a new type of over-saturated brine cement slurry was established. The density of cement slurry was design to be as high as 2.30 g/cm~3, in order to eliminate the potential plastic deformation of anhydrite formation. The formula of cement slurry was systematically optimized by evaluating the applied performance in the considered content range of additives, using the one-factor method. The results showed that, the over-saturated brine cement slurry designed here exhibits excellent and robust property such as those of thickening, compressive strength, fluid loss, and rheology, which can not only meet the cementing requirements on-site, but also supply key information and technology support for development of cement slurry family.