Non-Local Damage Modeling of Rocks under the conditions of High Pressure and High Temperature (HPHT)

This work is an attempt to develop a physically realistic model to understand the behavior and failure of rocks, especially under the extreme conditions of High Pressure and High Temperature (HPHT). A platform is laid in the preliminary work where 1D pure and ductile damage models are developed respectively. These models are based on an elasto-plastic model with an additional governing equation incorporated to facilitate the inclusion of damage. This additional governing equation is called the damage evolution equation. In the ductile damage model, it is assumed that the damage is driven and controlled by plasticity. The concepts developed in the preliminary work of 1D modeling are then taken into the study of 3D problems. The main problems studied are: the unconstrained uniaxial compression, the completely constrained uniaxial compression and the dynamic indentation problem. The dynamic indentation problem is the representation of an idealized rock drilling process. The results from the indentation problem are found to be in good qualitative agreement with the experimental results (Abd Al-Jalil, Y.Q 2006).