Development and Application of Innovative Anti-Leakage Tubing String for Low-Pressure Wax-Containing Wells

During the mid-to-late stages of oilfield development, reservoir energy depletion and declining formation pressure coefficients are prevalent challenges. To address the issues of severe fluid loss and extended post-workover fluid recovery periods during conventional operations such as thermal wax removal and pump inspection in low-pressure, waxy wells within a specific block of the Xinjiang Oilfield, a dynamic loss analysis model for workover fluids was developed. Additionally, a wash pressure control valve was engineered to meet the requirements for squeeze killing under abnormal conditions, and an integrated anti-leakage tubing string was designed. This system effectively isolates the workover fluid from the reservoir during interventions, thereby significantly reducing fluid loss and enhancing operational safety. Field applications demonstrate that this technology reduces workover fluid loss by 96% during thermal wax removal and shortens the average post-workover fluid recovery period by 8.7 days after pump inspection. This technology enables rapid restoration of well productivity, lowers operational costs for thermal wax removal and pump inspection, and provides an effective solution for maintaining low-pressure, waxy wells.