Insights into the hydro-mechanical behavior of a decimeter-scale fracture using the mini-SIMFIP probe

Conference · Sun Jun 08 00:00:00 EDT 2025

DOI:https://doi.org/10.56952/arma-2025-0361· OSTI ID:3028740

Osten, J; Jalali, M R; Amann, F; Cadmus, A; Cook, P J; Guglielmi, Y

ABSTRACT: Understanding hydro-mechanical couplings in fractured rocks is essential for predicting the rock mass response during high-pressure fluid injection, including the stimulation of enhanced geothermal systems. However, fluid-driven fracture dislocations are challenging to measure due to the need for local displacement data at high fluid pressures. In this study, fluid-driven displacement across a decimeter-scale laboratory fracture was investigated using the mini-SIMFIP (step rate injection method for fracture in-situ properties) probe, which is a smaller version of the SIMFIP tool (Guglielmi et al., 2014). The mini-SIMFIP probe is able to resolve the full 3D displacement vector of a fracture. The probe was installed in one of two boreholes across a decimeter-scale saw-cut granite fracture. Two pressure step injection tests were conducted under the same isotropic stress conditions. By varying injection between the boreholes, we estimated the aperture profile across the fracture. The results show a consistent pressure-dependent opening as long as steady-state flow was maintained. At a certain pressure step, steady-state conditions were no longer achievable and the fracture opened rapidly. The pressure-opening relationship diverged between the two tests and indicated a homogenization of the aperture profile and an increase in the non-linearity of the flow regime.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: US Department of Energy; USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23), Climate and Environmental Sciences Division (SC-23.1 )
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 3028740
• Resource Type: Conference paper
• Conference Information: 59th U.S. Rock Mechanics/Geomechanics Symposium
• Country of Publication: United States
• Language: English