Cement paste stratification at critical cementing point

The relevance of this research is driven by the necessity to investigate and predict the technological parameters of grouting mixtures in conditions that closely resemble real-world scenarios. The subject of this study is a grouting compound used in well construction, which serves to ensure the adhesion between the casing and the formation, strengthen the borehole walls, and prevent the leakage of underground fluids. The objective is to develop a methodology for investigating the cement mixture formation based on both theoretical and empirical data, with the aim of most accurately representing the actual behavior of the grouting solution within the annulus of a wellbore. The authors have proposed a model for two types of cement mortar structures. A method for examining the sedimentation stability of cement mortars using a specially designed experimental setup and monitoring protocol is presented. The analysis of samples collected at the proposed site allows us to study changes in the density of cement slurry over time, while simulating the behavior of cement in the annulus during the first hour of pumping. The findings indicate a tendency towards thickening and hardening of the cement mixture, as well as highlight potential issues that may arise when the cement composition does not meet the requirements set by downhole conditions. The statistical analysis of measured data demonstrates good reproducibility with low error, allowing us to simulate deposition of cement under various conditions. The results and the proposed recommendations for improving cement stability will be of value to technical experts and researchers, enabling them to achieve the objectives of environmentally friendly, time-efficient, and economically viable well construction.