(1. State Key Laboratory of Coal Mine Disaster Dynamics and Control，Chongqing University，Chongqing 400044，China；
2. National and Local Joint Engineering Laboratory of Gas Drainage in Complex Coal Seam，Chongqing University，
Chongqing 400044，China)
Abstract：Supercritical carbon dioxide(SC-CO2) jet breaking shale is a prominent shale gas drilling method. The shale sample of Longmaxi Formation was collected from southeast of Chongqing area. Based on the experiment platform of SC-CO2 jet breaking rock，the collected shale samples were impact by the SC-CO2 jets with varied jet pressures. The micro changes between original and eroded shale samples were studied utilizing CT，SEM/EDX，XRD and XRF methods. It’s indicated that the collected shale is characterized by low porosity，high clay mineral content and concordant bedding；impacted by SC-CO2 jet，the end face of shale core take on grid-like broken phenomenon，while it takes on large volumetric layered broken phenomenon on the whole；the erosion of shale mineral induced by SC-CO2 may caused the changes of micro-structure of shale，which may reduce mechanical strength of shale and is conducive to the rock breaking.
2015, Vol. 34 
