层理性页岩水平井井壁稳定性分析.pdf

46 4 () Vol.46 No.4 2015 4 Journal of Central South University (Science and Technology) April 2015 DOI: 10.11817/j.issn.1672-7207.2015.04.027 ( 610500) ()() 0°~30° 30°~90° 0.45 g/cm3 3 0.54 g/cm W201-H1 TE21 A 1672−7207(2015)04−1375−09 Analysis of wellbore stability for horizontal wells in stratification shale MA Tianshou, CHEN Ping (State Key Laboratory of Oil Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China) Abstract: Based on the poroelastic mechanics and the single weak-plane strength theory, the wellbore stability mechanics model of horizontal wells for stratification shale was established, so as to the influence of the bedding occurrence (strike, dip), hole trajectory (hole azimuth) and weakened strength of bedding planes on wellbore stability of horizontal well was analyzed. The results show that the occurrence of stratification and weakened strength of stratification are major factors causing wellbore collapse. When the bedding dip is 0°−30°, the wellbore stability is relatively poor, whatever azimuth of horizontal well is drilled. When the bedding dip is 30°−90°, the wellbore stability is better when horizontal well is drilled along a particular azimuth. These provide an important foundation for the azimuth optimization of h