Carlo Peruzzo awarded the best paper award at the ARMA Symposium

The awarded research, result of the PhD thesis of Carlo Peruzzo at EPFL Geo-Energy Laboratory - Gaznat chair, has quantified the effect of fracture toughness variation on vertical hydraulic fracture growth. In particular, it investigated the propagation of a hydraulic fracture driven by the injection of a viscous fluid through multiple layers of piece-wise homogeneous toughness. While the fracture propagates through the heterogeneous medium the instantaneous velocity of propagation at a generic position along the front oscillates around an average velocity that evolves with time. The research demonstrated that the ratio between the vertical and the horizontal average velocities tends to two different asymptotic limits. In one case this limit is zero, resulting in a “late time” contained vertical growth. In the other case, the ratio between the two velocities tends to be a non-zero constant, implying that the fracture grows with a constant aspect ratio.

These results have important practical applications in relation to well stimulation by hydraulic fracturing for geothermal energy production as well as gas storage (CO2, H2) and in-situ stress measurements.