Close Observation of Hydraulic Fracturing at EGS Collab Experiment 1: Fracture Trajectory, Microseismic Interpretations, and the Role of Natural Fractures

Fu, Pengcheng; Schoenball, Martin; Ajo‐Franklin, Jonathan; Chai, Chengping; Maceira, Mónica; Morris, Joseph P.; Wu, Hui; Knox, H. A.; Schwering, Paul; White, Mark D.; Burghardt, Jeffrey; Strickland, Christopher E.; Johnson, Timothy C.; Vermeul, Vince R.; Sprinkle, Parker; Roberts, Benjamin Q.; Ulrich, Craig; Guglielmi, Yves; Cook, Paul; Dobson, Patrick; Wood, Todd; Frash, Luke P.; Huang, Lianjie; Ingraham, Mathew Duffy; Pope, J. S.; Smith, Megan M.; Neupane, Ghanashyam; Doe, T.; Roggenthen, William; Horne, Roland N.; Singh, Ankush; Zoback, Mark D.; Wang, Herb; Condon, K. J.; Ghassemi, Ahmad; Chen, Hao; McClure, Mark; Vandine, George; Blankenship, Douglas A.; Kneafsey, Timothy J.

doi:10.1029/2020jb020840

Cited by 42 publications

(22 citation statements)

References 60 publications

(87 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On May 22, 2018, a 1 m interval of the injection borehole (I) centered at 50.3 m (165 ft) from the borehole collar was isolated using a high‐pressure straddle packer and stimulated to produce a hydrofracture as shown nominally in Figure 2a. During stimulation, the production borehole was left open to the atmosphere, and high‐pressure jet flow was observed (using a borehole camera) entering the borehole through hairline fractures over an approximately 2m interval near the anticipated hydro‐fracture/P‐well intersection (Fu et al., 2021). The same injection interval was later re‐isolated and used for the flow testing described in this study.…”

Section: Methodsmentioning

confidence: 99%

4D Proxy Imaging of Fracture Dilation and Stress Shadowing Using Electrical Resistivity Tomography During High Pressure Injections Into a Dense Rock Formation

et al. 2021

Self Cite

View full text Add to dashboard Cite

Understanding the state and evolution of subsurface stress is critical for developing effective strategies for extracting geothermal and fossil energy resources, sequestering carbon in geologic repositories, managing the risk of induced seismicity, and protecting the environment (U.S. Department of Energy, 2015). Subsurface energy production and carbon sequestration objectives require adequate understanding and control of subsurface fluid flow. The hydrogeologic properties that govern fluid flow are altered by significant changes in stress state (Ito & Hayashi, 2003;Min et al., 2004;Zoback & Byerlee, 1975). For example, during reservoir stimulation injections, deformations caused by changes in fluid pressure can cause existing fractures to open, close, or shear even at locations away from, and without direct hydraulic connection to the injected fluid. Interactions between stress and hydraulic properties often result in complex and evolving fluid flow fields both during and after fluid injections and extractions. Understanding these site-specific interactions over time will enable improved understanding and control of stress-sensitive fractured rock flow systems.

show abstract

Section: Methodsmentioning

confidence: 99%

4D Proxy Imaging of Fracture Dilation and Stress Shadowing Using Electrical Resistivity Tomography During High Pressure Injections Into a Dense Rock Formation

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…Following hydraulic fracturing convention, our drilling plan followed the common practice of drilling the injection and production wells parallel to the minimum principal stress, which at E1 was to the north and slightly dipping downwards. Owing to intense natural fracturing in and around the E1 site, we were aware of the potential for natural fracture shear stimulation and that one prominent foliation‐parallel permeable natural fracture (also called “OT‐P connector” by Fu et al., 2021) was close to the injection well. However, this natural fracture was not considered in the hydraulic fracturing design.…”

Section: Application To Egs Collab Experiments 1 and 2 Sitesmentioning

confidence: 99%

“…When E1 was hydraulically stimulated, field data provided clear evidence that the fluid injection stimulated new hydraulic fractures and also produced flow through this prominent foliation‐parallel natural fracture. This data set included microseismic mapping, tracer circulation tests, and direct visual observations of flow into the production well (Fu et al., 2021). The field observation of these permeable fractures parallel to foliation is consistent with our laboratory based predictions that foliation‐parallel fractures are the most likely to be permeable.…”

Section: Application To Egs Collab Experiments 1 and 2 Sitesmentioning

confidence: 99%

Hydro‐Mechanical Measurements of Sheared Crystalline Rock Fractures With Applications for EGS Collab Experiments 1 and 2

Meng

Frash

et al. 2022

JGR Solid Earth

Self Cite

View full text Add to dashboard Cite

Geothermal energy is attractive because it helps secure energy supply, mitigate climate change, and comply with future green energy policies. The GeoVision study estimates a potential 26-fold increase from 2019 geothermal energy production levels to 60 GW by 2050 in the United States (Bromley et al., 2010;Dobson et al., 2017;Fan, 2020;Hamm, 2019). To expand geothermal energy production, enhanced geothermal system (EGS) is a key candidate technology (Tester et al., 2006). Hydraulic fracturing is a stimulation method for EGS, where high injection pressures are used to create tensile fractures. Hydroshearing is another closely related stimulation method where fluid injection increases pore pressures and then triggers slip along pre-existing fractures. Both

show abstract

“…A handful of in situ field experiments have been conducted in recent years (Fu et al, 2021;Hertrich et al, 2021;Ingraham, 2021;Krietsch et al, 2020;Ma, 2021;Schoenball et al, 2020), which have significantly advanced our understanding of the hydro-seismo-mechanical processes at decameter scales; however, to what extent such experiments are representative of the realistic in situ heterogeneous rock mass remains an open question. As an effort to step up the scale towards hectometer rock masses (Gischig et al, 2020), the Bedretto Underground Laboratory for Geosciences and Geoenergies ('Bedretto Lab' hereafter) was established by ETH Zürich in 2018.…”

Section: Introductionmentioning

confidence: 99%

Multi-disciplinary characterizations of the Bedretto Lab – a unique underground geoscience research facility

Hertrich

Amann

et al. 2021

Preprint

View full text Add to dashboard Cite

Abstract. The increased interest in subsurface development (e.g., unconventional hydrocarbon, deep geothermal, waste disposal) and the associated (triggered or induced) seismicity calls for a better understanding of the hydro-seismo-mechanical coupling in fractured rock masses. Being able to bridge the knowledge gap between laboratory and reservoir scales, controllable meso-scale in situ experiments are deemed indispensable. In an effort to access and instrument rock masses of hectometer size, the Bedretto Underground Laboratory for Geosciences and Geoenergies (‘Bedretto Lab’) was established in 2018 in the existing Bedretto Tunnel (Ticino, Switzerland), with an average overburden of 1000 m. In this paper, we introduce the Bedretto Lab, its general setting and current status. Combined geological, geomechanical and geophysical methods were employed in a hectometer-scale rock mass explored by several boreholes to characterize the in situ conditions and internal structures of the rock volume. The rock volume features three distinct units, with the middle fault zone sandwiched by two relatively intact units. The middle fault zone unit appears to be a representative feature of the site, as similar structures repeat every several hundreds of meters along the tunnel. The lithological variations across the characterization boreholes manifest the complexity and heterogeneity of the rock volume, and are accompanied by compartmentalized hydrostructures and significant stress rotations. With this complexity, the characterized rock volume is considered characteristic of the heterogeneity that is typically encountered in subsurface exploration and development. The Bedretto Lab can adequately serve as a test-bed that allows for in-depth study of the hydro-seismo-mechanical response of fractured crystalline rock masses.

show abstract

Close Observation of Hydraulic Fracturing at EGS Collab Experiment 1: Fracture Trajectory, Microseismic Interpretations, and the Role of Natural Fractures

Abstract: The final version of the above article was posted prematurely on 16 July 2021, owing to a technical error. The final, corrected version of record will be made fully available at a later date.

Cited by 42 publications

References 60 publications

4D Proxy Imaging of Fracture Dilation and Stress Shadowing Using Electrical Resistivity Tomography During High Pressure Injections Into a Dense Rock Formation

4D Proxy Imaging of Fracture Dilation and Stress Shadowing Using Electrical Resistivity Tomography During High Pressure Injections Into a Dense Rock Formation

Hydro‐Mechanical Measurements of Sheared Crystalline Rock Fractures With Applications for EGS Collab Experiments 1 and 2

Multi-disciplinary characterizations of the Bedretto Lab – a unique underground geoscience research facility

Contact Info

Product

Resources

About