深水测试管柱接触非线性力学行为

针对深水测试管柱作业过程中的大位移和管柱接触问题，建立深水测试管柱管中管接触非线性耦合分析模型，依据深水测试海况环境和工艺参数施加载荷条件，研究深水测试管柱在典型作业工况下的力学性能和接触规律。研究表明：深水测试管柱的等效应力自上而下逐渐减小，加压射孔和关井回压属于深水测试管柱服役周期中的危险工况；测试管柱顶部位置、下挠性接头和扶正器邻近区域是深水测试管柱的强度弱点，在检测、维修时需要特别关注；深水测试管柱服役过程中与隔水管之间表现出随机接触的规律，测试管柱下挠性接头处接触载荷最大，是深水测试管柱的接触弱点；提高隔水管顶张力和下挠性接头转动刚度、控制浮式平台的作业范围有利于降低下挠性接头处的接触力，减小摩擦和磨损的发生。
In view of the large displacement and contact problems in the service cycle of test strings, a pipe-in-pipe model with nonlinear contact for deep-water test strings was established. The mechanical properties and contact characteristics in typical operation modes were studied, and the boundary conditions were applied based on the operation environment and technical parameters during deepwater testing. The study results show that the equivalent stress of the test string decreases from the top to bottom gradually. The pressure perforating mode and shut-in mode would be risky in the service cycle of deepwater strings, and extra attention should be paid on the string units adjacent to the top of test strings and the lower flex joint where the stress level is much higher. Random contact pattern is found between the test string and riser during the service cycle of the deep-water test string system. The maximum contact load (weak contact point) is found at the lower flex joint of the test string system. Three methods can be given to reduce the contact load at the lower flex joint and thus to reduce the friction and wear, i.e., improving the tension of the riser top and rotational stiffness of the lower flex joint, and controlling the drift distance of the floating platform