Fracture Detection of Lab Scale Energetic Stimulation

ABSTRACT: Stimulation of lab scale boreholes was studied using small explosives for improving the development of fracture networks in engineered rock surrogates. The experimental series examines the confluence of initial stress states, orientation of induced discontinuities and their interaction with source generated fracture growth. Density and stress response to the energetic was measured using high-speed schlieren imaging through the transparent polymethyl methacrylate (PMMA) sample. Outer surfaces were instrumented with an acoustic emissions (AE) array to detect 3D location of fracture evolution between wellbores. Prior to testing, the experiments were simulated to predict the generation of a shock induced fracture network between single and multiple wellbores in a variety of stress states. The quantification of wave arrivals, fracture growth, and development of the fracture network in transparent PMMA material is used as further validation against computational models. Understanding the conditions under which fractures propagate in the multivariate environment with small energetics results in improved modeling capability of larger scale wellbores and sources. The present work is part of a broader effort to accurize computational models necessary to predict formation interconnectivity established with energetics in low permeability reservoirs typical of enhanced geothermal systems (EGS).