A novel collapse pressure model with mechanical-chemical coupling in shale gas formations with multi-weakness planes

The shale gas reservoirs are usually characterized by tight matrix, rich in clay minerals, well-developed bedding planes and micro-fissures, which makes it highly water-sensitive and strong anisotropic, therefore the most important factors of wellbore instability for horizontal drilling in shale gas reservoirs are mainly the mechanical-chemical coupling. But apart from known problems until now drilling engineers still face the wellbore collapse...