张卫东, 常龙, 高佳佳. 横观各向同性地层井壁应力分析[J]. 工程力学, 2015, 32(11): 243-250. DOI: 10.6052/j.issn.1000-4750.2014.04.0348
引用本文: 张卫东, 常龙, 高佳佳. 横观各向同性地层井壁应力分析[J]. 工程力学, 2015, 32(11): 243-250. DOI: 10.6052/j.issn.1000-4750.2014.04.0348
ZHANG Wei-dong, CHANG Long, GAO Jia-jia. STRESS ANALYSIS AT THE BOREHOLE WALL IN TRANSVERSE ISOTROPIC FORMATIONS[J]. Engineering Mechanics, 2015, 32(11): 243-250. DOI: 10.6052/j.issn.1000-4750.2014.04.0348
Citation: ZHANG Wei-dong, CHANG Long, GAO Jia-jia. STRESS ANALYSIS AT THE BOREHOLE WALL IN TRANSVERSE ISOTROPIC FORMATIONS[J]. Engineering Mechanics, 2015, 32(11): 243-250. DOI: 10.6052/j.issn.1000-4750.2014.04.0348

横观各向同性地层井壁应力分析

STRESS ANALYSIS AT THE BOREHOLE WALL IN TRANSVERSE ISOTROPIC FORMATIONS

  • 摘要: 目前关于实钻井壁应力分布计算大都基于岩石的各向同性,在实际工况分析中存在误差。该文应用各向异性材料力学理论,将层状地层简化为横观各向同性岩石材料,建立了各向异性地层井孔周围应力计算模型。应用弹性力学广义平面应变问题的复变函数解法,结合井孔周围受力边界条件及相关坐标转换,得到横观各向同性地层斜井壁围岩应力解析解。对井壁围岩主应力影响因素的分析表明,层理面弹性参数、层理面倾角、水平原地应力比和井斜角方位角对井壁应力分布均会造成影响。在进行层理性地层井壁稳定分析时,应格外注意层理面倾角、原地应力比以及井斜参数的影响。该结果对现场施工设计有很好的指导意义。

     

    Abstract: Most of the existing models for borehole wall stress are based on isotropic rock. Thus, some errors may be generated under actual working conditions. In this research, according to the theory of mechanics of anisotropic materials, the bedded formation is simplified as transversely isotropic rock material, and a calculation model for stress around the borehole in anisotropic formations is developed. Based on the complex function solution of generalized plane strain elasticity problems, the circular-hole boundary conditions of the stress distribution, and the coordinate transformation, the stress distribution at the borehole wall in a transverse isotropic formation is investigated. A parametric study is carried out to investigate the effect of the elastic parameters, bedding plane inclination and orientation, ratio of horizontal in-situ stress, borehole deviation, and azimuth angle on the principal stress distribution. Results indicate that in the analysis of wellbore stability in bedding shale, special attention should be paid to the effect of bedding plane inclination, the in-situ stress ratio, and the borehole deviation parameters. The results are useful to construction site design before drilling.

     

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