Erosion prediction of bypass crossover sub in eccentric operating positions in horizontal wells

Abstract

Erosion wear is a serious problem in the fracturing process. The erosion of the bypass crossover sub, particularly in eccentric position, during fracturing in high flow rate and high proppant concentration can make a big difference in erosion results. CFD technology with Euler–Lagrangian approach is employed to solve the continuous phase and the discrete phase. In the fluid phase, realizable k−ϵ model was used to calculate the turbulent flows, and the Lagrangian method was applied to track the particle motion in the solid phase. In order to validate the accuracy of numerical simulation, scale model testing is used to obtain velocity of flow field in bypass crossover sub. The velocity profile is measured by a laser Doppler Anemonmetry (LDA). CFD simulation results are in a good agreement with experiment data. In this study, the particle trajectories and volume fraction in central and eccentric positions were obtained by simulation. This work aimed to conduct a detailed study on the flow phenomena of bypass crossover sub and analyze the difference in the bypass crossover sub between central and eccentric positions in terms of the magnitude of erosion rates and severe erosion locations and find out which erosion model is the most applicable to predict erosion. The numerical results show that the erosion contours predicted by the three erosion models have huge differences. Oka et al. erosion model is in a good agreement with practical observations by analyzing erosion patterns of the three erosion equations at specified locations and comparing them with actual image. The simulation of different flow rates and sand volume fraction were carried out. This research can help predict the erosion of bypass crossover sub more accurately and provide references for erosion prediction, as well as experiences for designing and improving the bypass crossover sub of horizontal wells in engineering.