【摘要】 由于问题的复杂性,在以往研究井壁稳定性的文献中,大多将地层介质简化为各向同性的。该文基于各向异性弹性理论,利用复变函数方法,建立了各向异性地层中倾斜井孔周围应力场的计算模型,得到了能够反映地层各向异性性质、地层倾向和走向、井斜角和方位角、井孔液柱压力、原始地应力方位和原始地应力比等多种因素影响的井孔周围应力场的解析表达式,以应力等值线云图表示的计算结果在一定程度上可以预测井壁开裂或坍塌的位置、范围、深度乃至坍塌后井孔的形状,为各向异性地层中井壁的稳定性分析和井孔轨道的优化设计提供了更切合工程实际的理论依据。更多还原

【Abstract】 Because of the complexity of the problem,most of the studies on borehole stability simplify the geologic medium as isotropic.Based on the theory of anisotropic elasticity,this paper established a model to calculate the stress distribution around an inclined borehole in anisotropic formation by means of complex function method.The analytical expressions for the stress field are formulated which can reflect the influences of the formation anisotropy,the bedding plane inclination and orientation,the borehole deviation and azimuth angles,the pressure of the drilling slurry,the direction and the ratio of the in-situ stresses.The stress contour maps obtained can be used to estimate the position,the extent,the depth and even the shape of fractured or collapsed borehole.The formulation might provide a more realistic basis of theory for analyzing the stability of the wellbore and optimizing the well trajectory in anisotropic formation.更多还原