1Section 4.8 Geoenergy, GFZ - German Research Centre for Geosciences, Potsdam, Germany; 2Section 2.6 Seismic Hazard and Risk Dynamics, GFZ - German Research Centre for Geosciences, Potsdam, Germany; 3Korea Institute of Civil Engineering and Building Technology, Goyang, Korea; 4Department of Energy & Resources Engineering, Korea Maritime & Ocean University, Busan, Korea
This study investigates numerically several hydraulic fracturing experiments that were performed on intact cubic Pocheon granite samples applying different injection protocols. The goal of the laboratory experiments is to test the concept of soft stimulation method which aims to increase permeability and to mitigate the risk of larger seismic events. The Irazu numerical code is used to simulate fully coupled hydraulic diffusion and fracturing processes including the detection of acoustic emission (AE) events under true-triaxial stress conditions. Our ongoing study focuses on the connection between the volume of infiltrated domains, the geometry of hydraulic fractures (including fracture pattern and volume) as well as the number and amplitude of AE events. This may lead to a better understanding of the link between observed injectivity improvement and induced seismicity. The preliminary results show that the code is capable of capturing certain characteristics of hydraulic fracturing tests. Improved numerical model may enable studying alternative injection schemes to provide basis for optimized stimulation design for future studies.