A Skin Factor Model of Sliding Sleeve and its Production Optimization

In order to effectively alleviate the problem of premature water breakthrough in horizontal wells, sectionalized variable-density perforation completion, stinger completion, ICDs and sliding sleeve based on control valve completion technology have been proposed. The sliding sleeve based on control valve completion technology can realize infinite adjustment and real-time control of the sliding sleeve opening to balance inflow effectively. In order to study the interference of the sliding sleeve completion to the flow near the wellbore, a calculation model for the skin factor of sliding sleeve is established in this paper. Based on numerical simulation, the flow area is divided according to the pressure distribution characteristics during the flow process of the sliding sleeve completion. At the same time, the linear flow boundary and the radial flow boundary are determined by combining the geometric boundary and roundness. Finally, the skin factor is determined according to the flow difference between the fluid passing through the sliding sleeve completion and the open hole completion, and it is compared and verified with the theoretical prediction value. The research shows that the flow in the near-wellbore of the sliding sleeve can be divided into six different zones according to the distribution characteristics of the pressure equipotential line. The radius of disturbance in the near-wellbore predicted by roundness is within 6% error of the numerical simulation results. By simulating the flow difference during constant pressure production, the error between the skin coefficient obtained by inverse calculation and the theoretical prediction value is within 12%. It was also observed that the water-cut decreased by 6.4% with the application of sliding sleeve completion compared to the normal screen pipe completion after 2 years of production. The proposed model is robust and reliable. The skin factor model in this study can be applied not just to the optimal design of water control completion parameters, but to provide theoretical guidance for the real-time regulation of the sliding sleeve opening during production.