Modeling dynamic stimulation of geological resources

Dynamic loading methods promise new modes for stimulating geological resources, as the fracture patterns they produce can be tailored by the shape and nature of the pressure pulse employed. However, selecting the type of load is a difficult task: Too slow and the stimulatory effect is reduced; too fast and the resource may be negatively impacted by wellbore damage, fines creation or permeability reduction. Moreover, modeling these systems proves challenging due to the myriad of length and timescales involved, combined with the need to accommodate both the generation of new fractures and propagation of preexisting fracture networks. This paper will discuss simulation of dynamic fracture initiation and propagation using Lawrence Livermore's GEODYN-L code. GEODYN-L is a massively-parallel multi-material Lagrangian code that includes advanced contact models to simulate nonlinear wave propagation through heavily-jointed rock masses, along with material model libraries specifically developed to capture the dynamic response of geologic media. We present results using GEODYN-L to simulate dynamic stimulation of geologic resources with pre-existing fracture networks and discuss the implications of these results for enhancing fracture networks with dynamic loading techniques. Prepared by LLNL under Contract DE-AC52-07NA27344.