The current research on the stability of the formation - cement sheath - casing combination is mainly based on the plane modelling, with established 3D model as just an example. There are no systematic studies of the three-dimensional model under triaxial ground stress when the influence of physical parameters on stability of the composite cementing interfaces is evaluated. By establishing a three-dimensional formation - cement sheath - casing combination, it was shown that the two cementing interfaces are separated under the action of triaxial ground stress. The effects of physical properties (elastic modulus, Poisson’s ratio, and density) of the cement sheath on the contact pressure and spacing of the cemented interfaces are studied. According to the established theoretical model, the influence of different physical parameters on well integrity after cementing in Qinghai Oilfield was analyzed, which provided theoretical support and guidance for the occurrence of out-of-tube turbulent flow and instability mechanism, and the direction for subsequent construction operations such as profile control and water plugging are pointed out. The results show that the physical properties of the cement sheath are critical in ensuring long-term sealing of the combination.

中文翻译：

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水泥护套物理参数对分离固井界面稳定性影响的三维数值模拟

目前对地层-水泥环-套管组合稳定性的研究主要基于平面建模，以建立的3D模型为例。在评估物理参数对复合胶结界面稳定性的影响时，没有对三轴地应力下的三维模型进行系统研究。通过建立地层-水泥环-套管三维组合，表明两个固井界面在三轴地应力作用下分离。研究了水泥环的物理性质（弹性模量、泊松比和密度）对胶结界面接触压力和间距的影响。根据建立的理论模型，分析了青海油田固井后不同物理参数对井完整性的影响，为管外湍流的发生和失稳机理提供了理论支持和指导，为后续的调剖、固井等施工作业提供了方向。指出水堵。结果表明，水泥环的物理特性对于确保组合的长期密封至关重要。