Improving the Accuracy of Refracturing Based on Solid Expandable Tubular: A Case Study

Summary Refracturing is a critical supplementary method for enhancing recovery from tight oil and gas reservoirs. The use of solid expandable tubular (SET) in wellbore reconstruction is beneficial for improving the accuracy of secondary fracturing. However, field reports indicate that the position of the SET after expansion deviates significantly from design, leading to the loss of certain fracturing sections and consequently affecting the overall production potential. To address this issue more effectively, we used a sequential coupling analysis method to examine the factors influencing the displacement of the SET during each operation stage, with the goal of determining the corresponding displacement. The results were then vector-superimposed to ascertain the final position, and field test data were utilized to evaluate the accuracy of the analysis. A case study conducted on Well X in western China demonstrates that both running and expansion pressure injection processes play significant roles in the downhole movement of SET. Notably, the displacement during the stable expansion stage is relatively controllable. The SET position derived from the analysis method shows strong consistency with logging data, validating the approach. Based on these findings, it is recommended to incorporate a buffer tube into the engineering design before deployment to mitigate the effects of downhole movement. The described workflow provides a cost-effective computational approach that may be adopted in other wells, facilitating the prediction of SET dislocation caused by specific operational procedures. Ultimately, this method aids in optimizing operational designs to enhance refracturing accuracy and improve the final recovery rate.