Brittleness and Fracability Evaluation of Unconventional Reservoirs Based on Energy

Yuan (Daniel) Hu


This work shows that elastic strain energy, plastic energy, damage energy and internal energy can be calculated using the FEM during rock failure. The simulation using the FEM to analyze an energy change and the degree of rock failure is validated by the axial compression tests. Confining pressure in the axial compression tests helps to create more cracks after the rock failure when input energy or loading is great enough and resist the rock from further failure when input energy is not enough. Coupled pore fluid diffusion and stress analysis models are used to simulate the process of hydraulic fracturing. Compared to a shale reservoir, a sandstone reservoir is higher in damage energy and energy efficiency during the simulation.