Study on Blowout Prevention Safety of Tubing Overflow Control Process String in Pumping Wells

To address blowout prevention safety hazards during rod and tubing tripping operations in Φ70 mm and larger sucker rod pump pumping wells, a tubing overflow control technology for pumping wells was developed through structural optimization and process innovation of the blowout preventer disconnect tool. Based on numerical simulation and theoretical analysis, a systematic safety evaluation of the blowout prevention tool was conducted: First, the mechanical strength reliability of the blowout preventer disconnect tool’s docking mechanism under complex working conditions was verified via finite element simulation. Second, by analyzing the buckling deformation characteristics of the sucker rod string and the mechanical behavior of the sealing system, the sealing failure mechanism of the blowout preventer disconnect tool while pulling the sucker rod, with its critical blowout prevention pressure threshold determined as 30.85 MPa. Finally, considering the mechanical load characteristics of the process string during the sucker rod retrieval process, a safety evaluation method for blowout prevention during the operation process of the tubing overflow control process string has been established. A safety evaluation chart for blowout prevention during the operation process has been designed, and the quantitative evaluation of blowout prevention safety during the operation process has been achieved. The research results provide theoretical support and technical guarantees for risk control in snubbing operations of pumping wells, offering significant engineering value for improving safety standards in oilfield operations.