非均匀的地应力下水泥环结构完整性规律分析

发布时间：2018-02-03 00:29

本文关键词： 完整性非均匀地应力井斜角水平井屈服强度　出处：《东北石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：油气井及储气库井套管试压、压裂及反复注采气等生产作业时,固井水泥环及其胶结界面会受到应力作用而产生变形甚至发生破坏,影响水泥环的封固效果。特别是当水泥环处于塑性非均匀应力地层中时,地应力非均匀性会导致应力、应变分布非线性变化,造成作业载荷加、卸载过程中水泥环及其胶结界面并存压缩、拉伸及剪切等复杂应力状态,为分析水泥环结构完整性增加了难度。为此,本文以水平井井眼条件为研究背景,建立了水平井地应力计算模型;利用有限元及弹性力学理论,分析了非均匀地应力条件下套管-水泥环-地层组合体力学作用关系,建立了接触有限元力学模型,建立了水泥环结构完整性评价准则;分析了载荷加载及卸载过程中地应力不均度、套管偏心状况、井斜角、水泥环力学参数等对水泥环界面应力及结构完整性影响及规律,评价了水泥环力学参数与结构完整性适应性问题,为合理选择水泥环力学参数,设计水泥浆体系提供了基础。研究结果表明,地应力不均度增加,水泥环受到的各应力分布不均匀性增加;而套管的偏心度大小,一定程度上加剧了水泥环受到的各应力分布的不均匀性;同时,井斜和井深的变化使井周地应力不均匀性增加,使水泥环受到的各应力出现明显变化;水泥环力学参数的变化使水泥环对非均匀地应力的响应不同,增加了水泥环受到的应力的变化。
[Abstract]:Oil and gas well and gas storage well casing pressure test, fracturing and repeated injection and gas production production, cement and cementing interface stress and deformation and failure, the effect of cement sheath sealing effect. Especially when the cement is plastic non uniform stress in the strata, stress non uniformity can lead to stress and strain distribution of nonlinear changes caused by work load, cement and cementing interface during unloading both compression, tensile and shear complex stress state, increase the difficulty for the analysis of cement ring structure integrity. Therefore, the horizontal well borehole conditions as the research background, calculation model the horizontal stress established; using finite element and elastic mechanics theory, analyzes the relationship between casing-cement combination of mechanical effect of non-uniform in-situ stress conditions, established the finite element contact mechanics model is established. The cement structural integrity evaluation criteria; analyzes the stress loading and unloading process irregularity, casing eccentricity, inclination, cement mechanical parameters and structural integrity of the effect and law of cement interface should be evaluated, and parameters of cement mechanical structure integrity adaptability, reasonable select the cement mechanical parameters, provides the basis for the design of cement slurry. The results show that the stress is to increase the degree of cement by the stress nonuniformity increase distribution; eccentric size and degree of casing, to a certain extent exacerbated by the cement stress distribution is not uniform; at the same time. Deviation and well depth change of the wells week of uneven stress increases, the cement ring is the stress changes; changes of cement mechanical parameters of the cement ring in response to non-uniform ground stress, increase A change in the stress of a cement ring.

【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE256

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