Abstract This study proposes a transient gas-liquid-solid multiphase flow model for gas kick during MPD, considering the effect of dynamic wellhead back-pressure, temperature field, and velocity relation of different phases. Based on this model, the gas kick control strategies and outflow response characteristics during MPD are thoroughly investigated. The simulated results reveal that, with the upward migration and expansion of the invading gas, the hydrostatic pressure and frictional pressure in the annulus changes accordingly, resulting in a non-linear relationship between the wellbore back-pressure and the bottom-hole pressure. Moreover, the effects of an under-balance pressure at the bottom hole, the pressure balance relationship between the formation and the bottom hole, the kick detection level, the well depth on the wellhead back-pressure control and the response behaviors of the outlet flow rate are discussed. The results of this investigation can provide engineering guidance for MPD to address the issue of gas kick.

中文翻译：

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控压钻井气涌井口背压控制策略及流出响应特性

摘要 本研究考虑动态井口背压、温度场和不同相速度关系的影响，提出了MPD期间气涌的瞬态气-液-固多相流动模型。基于该模型，深入研究了 MPD 期间的气涌控制策略和流出响应特性。模拟结果表明，随着侵入气体的向上运移和膨胀，环空内的静水压力和摩擦压力发生相应变化，导致井筒背压与井底压力呈非线性关系。此外，井底欠平衡压力的影响，地层与井底压力平衡关系，井涌检测水平，讨论了井深对井口背压控制和出口流量的响应行为。该调查结果可为 MPD 解决气涌问题提供工程指导。