深水隔水管系统安全作业窗口分析*

为分析深水隔水管系统在不同环境载荷下钻井平台允许的最大偏移量，确保整个钻井作业顺利完成并提高生产效率,建立隔水管-井口与土壤整体力学分析模型，提出1种以钻井平台向不同方向许可偏移距离确定安全作业窗口的分析方法，并结合实例分析表层海流速度及隔水管系统顶张力对隔水管系统安全作业窗口的影响。结果表明:当表层海流速度增大时，深水隔水管-井口与土壤整体系统安全作业窗口减小，不同模式间作业窗口的间距增大，且沿海流速度方向正常工作区间减小幅度远大于垂直海流速度方向，应尽早准备和启动隔水管系统底部脱离；当海流速度过大导致安全作业区间过小时，可通过提高隔水管系统的顶张力增大安全作业区间。

Analysis on safe operation window of deepwater riser system

In order to analyze the allowable maximum offset of the drilling platform for the deepwater riser system under different environmental loads,ensure the smooth completion of the whole drilling operation and improve the production efficiency,an integral mechanical analysis model of riser-wellhead and soil was established.An analysis method to determine the safe operation window according to the allowable offset distance of drilling platform in different directions was proposed,and the influence of surface sea current velocity and top tension of riser system on the safe operation window of riser system was analyzed by actual example.The results showed that when the velocity of surface sea current increased,the safe operation window of the integrated system of deepwater riser-wellhead and soil decreased,the spacing between the operation windows of different modes increased,and the decreasing amplitude of normal operation internal along the direction of sea current velocity was much larger than that in the direction vertical to sea current velocity,so the bottom detachment of the riser system should be prepared and started as soon as possible.When the sea current velocity was too large,which caused the too small safe operation interval,the safe operation interval could be increased by increasing the top tension of riser system.