Cementing displacement efficiency analysis in long horizontal wells: An optimized numerical simulation approach

Abstract Casing eccentricity reduces displacement efficiency during horizontal well. However, there are many problems such as the short length of horizontal well simulation and long calculation time now. In this study, the cement model was re-established based on the relative motion principle. Through the reverse movement of the wall, the short horizontal section model was realized to simulate the displacement process of the long horizontal section without generating new grids and the computational resources were greatly reduced. Besides, by redefining the displacement interface length and dynamic displacement efficiency, the precision problem of displacement efficiency parameter analysis in engineering is solved. The accuracy and practicability of this method were verified by comparing it with the previous research results. On this basis, the effects of the concentration, displacement, density difference and the rheological properties of the isolator were studied. The results show that it is beneficial to equalizing the velocity of the narrow and wide side, with the measure that decreasing the eccentricity, increasing the positive density difference or the viscosity difference of the two-phase fluid, thereby improving the displacement efficiency. This study provides a comprehensive modelling method for numerical simulation of cementing displacement and provides theoretical guidance for field cementing operations.