EGS Collab Experiment 1: SIMFIP Notch-164 GRL Paper

Characterizing the stimulation mode of a fracture is critical to assess the hydraulic efficiency and the seismic risk related to deep fluid manipulations. We have monitored the three-dimensional displacements of a fluid-driven fracture during water injections in a borehole at ~1.5 km depth in the crystalline rock of the Sanford Underground Research Facility (USA). The fracture initiates at 61% of the minimum horizontal stress by micro-shearing of the borehole on a foliation plane. As the fluid pressure increases further, borehole axial and radial displacements increase with injection time highlighting the opening and sliding of a new hydrofracture growing ~10 m away from the borehole, in accordance with the ambient normal stress regime and in alignment with the microseismicity. Our study reveals how fluid-driven fracture stimulation can be facilitated by a mixed-mode process controlled by the complex hydromechanical evolution of the growing fracture. The data presented in this submission refer to the SIMFIP measurements and analyses of the stimulation tests conducted on the 164 ft (50 m) notch of the Sanford Underground Research Facility (SURF), during the EGS-Collab test 1. In addition to the datafiles, there is the draft of a manuscript submitted to Geophysical Research Letters (GRL).

表征裂缝的激发模式，对于评估与深部流体作业相关的水力效率与地震风险至关重要。本研究针对美国桑福德地下研究设施（Sanford Underground Research Facility）结晶岩中约1.5千米深度的钻孔开展注水作业，监测了流体驱动裂缝的三维位移变化。裂缝通过钻孔在叶理面上的微剪切作用，在最小水平主应力的61%阈值处起裂。随着流体压力进一步升高，钻孔轴向与径向位移随注水时长增加而增大，表明距钻孔约10米处发育的新水力压裂裂缝发生张开与滑移，该现象与原位法向应力状态一致，且与微地震活动匹配。本研究阐明，由发育中裂缝的复杂流固力学演化所调控的混合模式过程，可有效促进流体驱动裂缝的激发作业。本投稿所呈现的数据，对应于桑福德地下研究设施（SURF）164英尺（50米）切口处开展的激发试验的SIMFIP测量与分析结果，试验属于EGS-Collab测试1项目。除数据文件外，本数据集还包含一篇投至《地球物理研究快报》（Geophysical Research Letters, GRL）的论文草稿。