油井水泥环环空封固可靠性力学分析与研究

项目名称： 油井水泥环环空封固可靠性力学分析与研究

项目编号： No.51474074

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 矿业工程

项目作者： 张景富

作者单位： 东北石油大学

项目金额： 85万元

中文摘要： 油气井生产过程中，作业载荷会对套管-水泥环-地层固结体产生力学作用，过高的载荷作用下可能因固结体内薄弱部位发生破坏而导致固结体出现裂纹或开裂解体，破坏水泥环密封可靠性，造成油气井井口冒油、冒气事故，影响油气开发与生产。为此，本项目以水泥环力学性能检测实验为基础，利用弹塑性力学理论研究油井水泥环环空封固可靠性问题。以分析三轴应力条件下水泥环应力-应变规律为基础，建立水泥环力学本构方程，研究套管-水泥环-地层固结体力学作用关系，分析水泥环胶结界面承载能力对固结体接触状态的影响，建立能适应于加载、卸载不同载荷作用方式的固结体弹塑性接触有限元力学模型，水泥环环空封固失效准则；分析计算载荷作用下水泥环及水泥环胶结界面应力状态、微裂纹发生状况，研究影响水泥环环空封固可靠性的因素及规律，提出改善和保障水泥环封固可靠性的途径及措施。为保障水泥环封固质量，保障油气井正常生产提供技术支持。

中文关键词： 水泥环；胶结；封固；可靠性；力学分析

英文摘要： Mechanical action on casing-cement sheathe-strata cemented combination would be produced by operation loads during the oil and gas production. The weak part in the cemented combination would be damaged under the condition of high operation load, which the crack or disintegration by structural fracture would be occurred in the combination. The sealing reliability of cement sheathe was damaged. The leakage accident of oil or gas would be created at the hole top, which could affect on the oil and gas production. For these reason, the problem of sealing reliability of oil well cement sheathe was studied by using plasto elasticity theory, based on the mechanical behavior tested in experiment of cement sheathe. The mechanical constitutive equation of cement sheathe was established according to the analysis for stress-strain law of cement stone tested at the tri-axial stress conditions. Mechanical action relationship in casing-cement sheathe-strata cemented combination was researched. The influence of cemented boundary bearing capacity on contact mode of the combination was analyzed. Contact finite element mechanical model and cement sheathe sealing failure criterion were created, which could be suit for action forms both of loading and discharging. Stress condition and micro-crack state caused in cement sheathe body and cemented boundary were calculated and analyzed. The affecting factor and law on the annular sealing reliability of cement ring was researched. Methods for improving and safeguarding the cement ring sealing reliability were presented, which could provide technical support upon insuring sealing quality and normal production.

英文关键词： Cement sheathe;cemented;sealing;reliability;mechanical analysis