考虑岩石力学参数变化的水平井套管强度安全评价研究

发布时间：2018-01-21 22:33

本文关键词： 水平井套管岩石力学岩石围压孔隙压力有限元　出处：《西安石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：在油气田开发开采过程中,尤其是在储层压裂施工过程中,套管时常发生损坏,套管损坏会造成注采系统不稳定、破坏油层甚至导致无法开采等事故发生,严重影响油气田的正常生产,使油田蒙受损失。对油气田现场损坏的套管调研发现,大量套管出现变形挤毁现象。考虑引发事故的原因为岩石的力学参数发生变化,这是由于注采制度的改变会引起孔隙压力的波动,进而影响到储层岩石的力学性质,从而威胁套管的强度安全。本文以水敏性泥页岩为研究对象,在原有应力分解增量中创新引入吸水应力增量概念,得到水敏性泥页岩修正本构理论,旨在提高原有的岩石类材料本构方程准确性,优化围岩模型。地层压力直接作用于水泥石环外壁,压力由水泥石环内壁传递至套管。由于水泥石环的材质、厚度和套管的钢级和管厚的不同,套管所受压力相较地层压力会发生不同程度的变化。所以综合考虑“套管-水泥石环-地层”体系耦合作用对水平井套管强度分析显得尤为重要。以套管为单一研究对象进行理论研究由于假设繁多使得分析结果和实际工况相去甚远。为此,本文以“套管-水泥石环-地层”耦合体系为载体,综合考虑压力从地层到水泥石环到套管的逐级传递对套管强度理论分析的影响,从而为优化“套管-水泥石环-地层”耦合体系打好基础。因为地层岩石材质不均匀及地层强度不稳定,分析地层岩石对“套管-水泥石环”体系影响比较困难,故以“套管-水泥石环-地层”体系作用下水平井套管强度研究的结果为基础。为此,本文以实际工况为例,以“套管-水泥石环-地层”耦合体系为研究对象,运用ANSYS有限元软件对其进行有限元模拟,分析不同地层岩石含水率对“套管-水泥石环-地层”耦合体系的影响。为复杂地质条件下水平井套管的选取提供指导性意见。
[Abstract]:In the process of oil and gas field development and production, especially in the process of reservoir fracturing, casing often occurs damage, casing damage will lead to instability of injection and production system, damage to reservoir and even lead to unexploitable accidents. It seriously affects the normal production of the oil and gas field and makes the oil field suffer losses. A large number of casing appear deformation and squeezing phenomenon. The reason of considering the accident is the change of rock mechanical parameters, which is due to the fluctuation of pore pressure caused by the change of injection-production system. Thus affecting the mechanical properties of reservoir rock, thus threatening the safety of casing strength. This paper takes the water sensitive shale as the research object, and introduces the concept of water absorption stress increment into the original stress decomposition increment. The modified constitutive theory of water sensitive shale is obtained in order to improve the accuracy of constitutive equation of the original rock material and optimize the surrounding rock model. The formation pressure acts directly on the outer wall of cement stone ring. The pressure is transferred from the inner wall of the cement stone ring to the casing. Due to the difference in material, thickness and steel grade and pipe thickness of the cement stone ring. Casing pressure will vary from formation pressure to formation pressure. System coupling is particularly important for casing strength analysis in horizontal wells. Taking casing as a single research object for theoretical research, the analysis results are very different from actual working conditions because of various assumptions. In this paper, the coupling system of "casing, cement stone ring and formation" is taken as the carrier, and the influence of the gradual transfer of pressure from formation to cement stone ring to casing on the theoretical analysis of casing strength is considered synthetically. Thus, it lays a good foundation for optimizing the coupling system of "casing, cement, stone ring and stratum", because the formation rock material is not uniform and the formation strength is unstable. It is difficult to analyze the influence of formation rock on the "casing cement stone ring" system, so it is based on the research results of casing strength in horizontal wells under the action of "casing cement stone ring formation" system. This paper takes the actual working condition as an example, takes the coupling system of "casing, cement stone ring and stratum" as the research object, uses ANSYS finite element software to carry on the finite element simulation to it. This paper analyzes the influence of rock moisture content in different formations on the coupling system of "casing, cement stone ring and stratum", which provides guidance for the selection of casing in horizontal wells under complex geological conditions.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE931.2

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