水泥环力学完整性系统化评价方法

在油气井生产周期的不同作业阶段,水泥环在前一阶段的受力状况会对后续生产阶段的力学响应产生影响,水泥环力学完整性的评价须系统化。类比于隧道开挖工程中需要添加支护结构支撑开挖后围岩收敛的过程,石油工程中的钻井过程与其有一定的相似之处。在弹塑性力学的基础上,将隧道收敛约束法引入石油工程中,提出水泥环力学完整性评价方法。结果表明,运用该方法不仅可以直观地描绘出水泥环的破坏形式,还可以对破坏程度进行量化,可用于水泥环完整性的系统化评价和钻井工程设计指导。

Systemic evaluation method of cement mechanical integrity

In the different operation phases of well life cycle, the stress of the previous phase in cement will affect the mechanical response of the subsequent phases. Therefore, the integrity evaluation of the cement mechanics needs to be systematic. By analogy with the process of adding structure to support the convergence of surrounding rock after excavation in tunneling engineering, the drilling process in petroleum engineering has a number of similarities. Based on elastic-plastic mechanics and combined with the convergence-confinement theory, a new system response curve method was proposed. The results show that this method not only can visually depict the failure mode of cement, but also quantify the degree of damage. It can be used for the evaluation of cement integrity and provide guidance for drilling engineering design.