深水井控的七组分多相流动模型

针对深水井控的特点，考虑深水钻井外部的多温度梯度环境和天然气水合物相变，将井筒内流体分为7种不同组分，建立了七组分井筒多相流控制方程。利用全尺寸实验井对井筒多相流动规律和井筒压力计算精度进行了验证。以墨西哥湾Mississippi Canyon井钻井工况为例，应用所建立的七组分多相流动模型算法，从溢流和井喷过程模拟、压井过程模拟及天然气水合物相变对井控参数影响等几个方面对深水井筒多相流动规律进行了分析。模拟发现，气体在沿井筒上升初期膨胀量比较小，进入隔水管内后开始明显膨胀，越靠近井口膨胀越剧烈。从溢流发展到井喷可分为3个阶段：井涌发展阶段、井喷阶段和井内喷空阶段。在井涌阶段末期，井底压力、泥浆池增量、隔水管内的气体体积分数等会发生剧烈变化，在极短的时间内演化为井喷。在深水压井过程中，由于节流管线内气体交换效应，节流压力的调节速度要高于陆地井控。由于水合物的生成，减小了泥浆池增量，降低了关井套压，给溢流的检测及气侵程度判断带来困难。

Application of a seven-component multiphase flow model to deepwater well control

In view of a multi-temperature gradient environment outside deepwater drilling wells and the phase transition of natural gas hydrates,the present paper divided the wellbore fluid into seven different components based on characteristics of deepwater well control and established a seven-component multiphase flow control equation.Multiphase flow experiments of wellbore were carried out on a full-scale test well and the calculation accuracy of wellbore pressure was verified.Taking a Mississippi Canyon drilling ...