Experimental Investigation of Hydraulic Fracture Closure in a Porous Sandstone

Depending on the type of fracture propagation regime when the injection stops, the closure of the fracture may occur exactly after the injection ceases, in the case where the fracturing process is dominated by fracture energy, or the fracture propagate for a while due to the elastic energy stored in the rock, when fluid viscous dissipation dominates. In any cases, fluid losses in the surrounding porous media ultimately stops fracture growth and the fracture closes (on the proppant pack in practice). Some recent theoretical solutions have been reported for the recession and closure of a hydraulic fracture in the absence of proppant. These solutions are relevant in the context of micro hydraulic fracturing tests for in-situ stress determination. In this work, we report a laboratory hydraulic fracture experiments performed in sandstones with the aim to study experimentally fracture closure. In our experimental set-up, an extensive passive acoustic monitoring is performed and provide un-precedented spatio-temporal evolution of fracture development and closure.