Laboratory validation of fracture caging for hydraulic fracture control

It is possible to engineer and control the extents of the stimulation rock volume for hydraulic fracturing. Currently, available tools and methods intended to accomplish this task focus on optimizing injection fluid properties, utilizing existing rock stress boundaries, controlling stimulation intervals in the injection well, and manipulating injection pressures and rates. What if it were possible to control hydraulic fracture extents more directly than these methods do and to have confirmation of these extents in the subsurface? For this, we propose a ‘fracture caging’ concept where an array of injection wells and production wells are drilled prior to stimulation as a means to identify and control the extent of a stimulated zone. Positive identification of stimulation extents occurs by monitoring production well pressures and flow rates. Control of fracture extents occurs by control of the production well pressures and arrangement of production wells so as to contain an intended stimulated zone. In this study, we present the fracture caging concept and validate it with laboratory experiments. Numerical modelling with LLNL’s GEOS code is used to predict the effectiveness of the fracture caging concept as it applies to the SIGMA-V (EGS Collab) geothermal energy research field site.