Research on plugging mechanism under blowout conditions for hole-type seal failure for blowout preventer

Abstract

Blowout preventers (BOPs) are critical for ensuring operational safety in oil and gas development. Seal failure can lead to catastrophic accidents, such as uncontrolled blowouts. In engineering applications, the injection of bridging particles has been proposed as a temporary solution to plug leak points, providing a crucial time window for emergency response. However, the existing plugging mechanism remains poorly understood, limiting the advancement of plugging techniques. To address this issue, a numerical model for BOP hole-type seal failure was developed in this study using computational fluid dynamics (CFD) and discrete element method (DEM) simulations. Fluid–structure coupling analysis was conducted to clarify the particle bridging and plugging process. The influence of key parameters—including wellhead pressure, particle shape, particle size, pumping displacement, and particle concentration—on the plugging effect was comprehensively investigated. The results indicate that under 10 MPa and 40 MPa conditions, rectangular or cylindrical particles are preferred to enhance the plugging success rate and stability. At 10 MPa, the pumping displacement should be less than 1.5 m³/min, and the particle concentration should exceed 8%. At 40 MPa, the pumping displacement should exceed 2.0 m³/min, and the particle concentration should be greater than 6%. For higher pressures (70 MPa), particles larger than the leak point size are recommended, with a pumping displacement exceeding 2.0 m³/min and a particle concentration greater than 8%. This study provides practical recommendations for pumping displacement and particle selection under blowout conditions, significantly improving the success rate and efficiency of plugging operations. It also serves as a valuable reference for the development of plugging processes and technologies for BOP seal failure.