The Effect of Anisotropy of Medium on the Stress State around a Borehole
Based on the analytical solution for the stress field around an inclined borehole in an anisotropic medium, a computer program was developed and a serial parametric study was conducted. The effects of parameters such as degree of anisotropy, borehole inclination, bedding plane inclination and in-situ stress conditions on the stress distribution around a borehole were evaluated. The results showed that medium anisotropy has little effect on borehole fracture analysis at low borehole inclinations, but its influence becomes significant for highly inclined boreholes. As the degree of anisotropy varies the maximum shear stress changes remarkably. This indicates that the degree of anisotropy plays a role in the collapse failure of a borehole. The information generated in these studies can be used in predicting the fracture or collapse-initiating pressures.
Yungang Li, Pengcheng Wang, Liqun Ai, Xiaoming Sang and Jinglong Bu
Y. S. Jiao et al., "The Effect of Anisotropy of Medium on the Stress State around a Borehole", Advanced Materials Research, Vols. 291-294, pp. 2139-2144, 2011