各向异性度对水平井井壁稳定性的影响

Influence of anisotropy on wellbore stability in horizontal wells

本文使用软件Matlab编程计算不同各向异性度井壁处最小主应力分量,然后通过拉伸失效准则和剪切失效准则来分析水平井壁的稳定性。结果表明:在不同的各向异性度下井壁切应力、最小主应力分布值之间都存在明显的差距,在应力最大值和最小值处这种差距体现得最为明显;对于不同各向异性度,最小主应力分布几乎与各向同性的应力分布一致;随着各向异性度的增加,井壁的拉伸失效趋势增加,而剪切失效趋势减小。

The paper is used the software Matlab program to calculate the stress component of the different anisotropic degree at the borehole wall. And then, the stability of horizontal borehole wall is analyzed by the tensile and the shear failure criterion. The results show, the shear and principal stress distribution of the wellbore are different under the different degree of anisotropy, and in the maximum and minimum stress the different is more obvious, the minimum principal stress distribution is almost consistent with the isotropic stress distribtion.With the increase of anisotropic degree, the tensile failure tendency of the borehole wall increase and the shear failure tendency decrease.