水平井多封隔器管柱力学分析及安全评价

针对水平井多封隔器管柱在井下多种载荷的共同作用下易引起管柱失效的安全问题，基于力学研究中的多杆件的多次超静定结构，引入力法对多封隔器之间管柱进行受力分析，同时考虑温度效应、活塞效应、鼓胀效应和螺旋屈曲效应的影响，建立考虑多封隔器影响的轴向力数学模型；在此基础上建立多封隔器管柱力学安全强度评价准则和封隔器控制信封失效判断方法，对现场水平井多封隔器管柱进行力学分析和安全评价。研究结果表明，建立的考虑多封隔器影响的轴向力数学模型计算结果大于常规不考虑多封隔器影响时轴向力，若不考虑多封隔器的影响将低估多封隔器管柱的轴向力，而造成管柱受力危险；同时对管柱危险位置和封隔器进行安全评价，得到了酸化作业时油压和套压的综合控制参数，以期为水平井多封隔器管柱安全工作参数的优化设计提供理论依据。

Mechanical Analysis and Safety Evaluation of Multi Packer String in Horizontal Well

In view of the safety problem that the string of multiple packers in horizontal wells is easily prone to string failure due to the combined action of various downhole loads, this paper introduces the force method to analyze the force on the multi-packer string based on the multiple statically indeterminate structure of multi-bar members in mechanical research. Considering the temperature effect, piston effect, bulge effect and spiral buckling effect, the axial force mathematical model considering the effect of multiple packers is established. Then, the evaluation criteria of mechanical safety strength of multi-packer strings and the judgment method of packer control envelope failure are established to conduct mechanical analysis and safety evaluation on multiple packer strings in horizontal wells. The study''s study showed that the developed axial force mathematical model''s calculation result, which takes into account the influence of multi-packers, is superior to the conventional axial force, which does not take into account the influence of multi-packers. The axial force of the multi-packer string will be underestimated and at risk of stress if the impact of numerous packers is not taken into account. The dangerous depth of the string and the safety evaluation of the packer are carried out simultaneously, the comprehensive control parameters of oil pressure and casing pressure during acidizing operation are obtained, which provides a theoretical basis for the optimization design of the safe operating parameters of multiple packer string in horizontal wells.