Optimizing Wellbore Deviation and Azimuth to Minimize Sand Production Using a Hybrid Numerical Model in a Southwest Iran Oilfield

The deviation angle of wellbores has a significant effect on sand production. Also, the direction of wellbores according to the field stresses is another effective parameter in increasing (or decreasing) the sand production rate. One of the limitations of modeling in the study of the sand production process is to provide a comprehensive three-dimensional model that can simulate all the real conditions of the reservoir, including the situations of the wells and the cavities. In this study, the variations in the sand production rate according to different wellbore inclinations and azimuths were investigated in one of the sandstone reservoirs of the Asmari formation located in the southwest of Iran. For this purpose, a finite difference model (FDM) was developed. Due to the complexity of the geometry of the reservoir, wellbore, and perforations in different situations and the inability of finite difference meshing in modeling such a structure, finite element meshing (FEM) was used. A discrete element model (DEM) was coupled with the finite difference model to simulate the sandstone reservoir. Fluid flow was added to the model using computational fluid dynamics (CFD). Using this FDM-DEM-FEM-CFD hybrid numerical model, the process of sand production in wellbores with different deviations and azimuths was investigated. The results of numerical models showed that according to the normal stress regime of the reservoir, vertical wells produce less sand in this oilfield than horizontal and deviated wells. Also, the highest amount of sand production is related to deviated wellbores, especially those drilled in the direction of minimum horizontal stress. In addition, in horizontal wells with a flow rate of 2000 bbl/day, the variation in the azimuth does not significantly affect the sand production rate.