Analysis of Methodology for Selecting Rheological Model of Cement Slurry for Determining Technological Parameters of Well Casing

The development of oil and gas infrastructure requires the development of new fields or the renewal of existing ones, which are mainly located in complex mining and geological conditions. Drilling intervals with abnormal formation pressures can cause a number of complications during cementing and subsequent well operation. The most common problem is inter-column pressures and cross-flow between formations. Gas migration may occur due to the fact that the mud has not been completely replaced by the cement slurry during cementing, and therefore there is no adhesion in the rock-cement contact zone. Understanding the process formation of cement slurry structural and rheological properties can reduce the risk of this problem and increase the casing anchoring efficiency. The study reveals that the rheological model of the same slurry can vary depending on various factors (temperature, water-cement ratio, cement slurry additives). Comparative results of laboratory studies on the effect of different concentrations of filtration loss reducer (FLR) from 0.1 to 0.5% and temperature in cement slurry are presented. As a result, the optimum concentration of FLR is selected, the range of which is from 0.2 to 0.3%. The analysis revealed that the accuracy of calculation of rheological parameters using the least squares method is higher than the industry standard. The deviation of numerical values of rheological model coefficients ranges from 7 to 60%. The approximation quality is assessed based on the sum calculation of the squared deviations.