Particle scale reservoir mechanics

This paper summarizes some developments and applications of discrete particle modelling based on the commercial code PFC (Particle Flow Code). The following examples with relevance to geomechanical reservoir behaviour are described: Numerical and experimental results are shown illustrating nonlinear evolution of depletion-induced compaction and stress path for simulated reservoir rock, i.e. materials that are formed under stress. This nonlinearity is often lost in core measurements, as a result of stress release during coring (core damage). Angular and breakable superparticles have been implemented in the particle model and applied to simulate the formation of a compaction band at high stress level. The model is also used to investigate the formation of a shear band at lower confinement. Numerical scheme of fluid coupling has been developed in both 2D and 3D models and applied to study stress-dependent permeability. Stress-dependency of the acoustic properties of a bonded particle assemblage has been studied. The preliminary results of the simulations with various developments show qualitative and also quantitative consistence with experiments. It proves the feasibility of applying a discrete particle model as a numerical laboratory to study particle scale reservoir mechanics.