Thermo-Hydro-Mechanical Behavior of the Rock Mass Surrounding Wellbore in Deep Saturated Geological Layer

In case of a wellbore drilled in poro-thermo-elastic rock, the process of wellbore drilling will result in thermic, hydraulic and mechanical phenomena which occur simultaneously and interact with each other. This study presents the analysis of the stress state around the wellbore located in the saturated rock at depth based on a fully coupling thermo-hydro-mechanical behavior model of the rock mass by the finite element method. Two scenarios related to thermal condition at well wall are taken into account, i.e., the drilling fluid temperature is inferior or superior to the temperature of the rock mass corresponding to the cases of “cooling” and “heating” the wellbore. The obtained results indicate that the thermic, hydraulic and mechanical phenomena in interaction with each other occurring in the material produce a large change in the stress state around the wellbore through the cases of cooling and heating. Effect of some thermic and hydraulic parameters of the rock mass on the stress state around the wellbore is also highlighted in this work.