Effect of Bedding Plane Occurrence on Horizontal Shale Gas Wellbore Stability

Unlike the homogenous sandstone reservoir of conventional energy,the reservoir of shale gas is well bedded,and occurrences differ.According to the rock mechanics tests of cores,the shale shows notable strength anisotropy due to the bedding planes.The results show that when the bedding plane tendency is parallel to direction of minimum horizontal stress,the collapse pressure will increase at first and decrease rapidly with the increase of bedding planes dip when drilling to the direction of bedding plane trend;the collapse pressure will keep constant when drilling to the direction of bedding plane strike.It provides a reference for drilling design of shale gas well.