Close Observation of Hydraulic Fracturing at EGS Collab Experiment 1: Fracture Trajectory, Microseismic Interpretations, and the Role of Natural Fractures
Year: 2021
Type: article
Abstract: Despite the wide application of hydraulic fracturing in enhanced geothermal system (EGS) development and unconventional hydrocarbon production, our understanding of the many factors affecting the propagation of hydraulic fractures has relied on circumstantial evidence. This is partly due to the scarcity of direct observations in the subsurface. The EGS Collab project attempts to address these issues in the context of EGS research by performing intermediate‐scale (∼10 m) hydraulic stimulation experiments in a thoroughly characterized and heavily instrumented underground testbed. This paper analyzes the data collected from the first suite of hydraulic fracturing tests in this testbed, consisting of seven stimulation episodes. High‐quality microseismic data delineate five planar features very clearly. Combining fracture‐wellbore intersection observations from distributed temperature sensing (DTS) and visual observations from an open‐hole well, as well as prior in‐situ stress measurements, we conclude with high certainty that the four larger planes were hydraulic fractures. The growth of the hydraulic fractures was temporarily halted by a prominent, open natural fracture in the testbed but they eventually crossed and slightly reoriented under continued stimulation. Mineral‐filled (i.e., healed) natural fractures, though prevalent in the testbed, did not have perceivable effects on hydraulic fracture propagation. The high‐quality, mutually corroborating data sets allowed conclusions to be drawn with high confidence and attests to the advantage of intermediate‐scale experiments in subsurface research.
DOI: 10.1029/2020jb020840
Authors: Pengcheng Fu, Martin Schoenball, Jonathan B. Ajo‐Franklin, Chengping Chai, Monica Maceira, Joseph P. Morris, Hui Wu, Hunter Knox, Paul C. Schwering, Mark D. White, Jeffrey A. Burghardt, Christopher E. Strickland, Timothy C. Johnson, Vince R. Vermeul, Parker Sprinkle, Benjamin Roberts, Craig Ulrich, Yves Guglielmi, Paul J. Cook, Patrick F. Dobson, Todd Wood, Luke P. Frash, Lianjie Huang, Mathew D. Ingraham, Joseph S. Pope, Megan M. Smith, Ghanashyam Neupane, Thomas W. Doe, William M. Roggenthen, Roland Horne, Ankush Singh, Mark D. Zoback, Herb Wang, Kate Condon, Ahmad Ghassemi, Hao Chen, Mark W. McClure, George Vandine, Douglas Blankenship, Timothy J. Kneafsey, EGS Collab Team
Institutions: Lawrence Livermore National Laboratory, Lawrence Berkeley National Laboratory, Rice University, Oak Ridge National Laboratory, Pacific Northwest National Laboratory, Sandia National Laboratories, Los Alamos National Laboratory, Idaho National Laboratory, Golder Associates (United States), South Dakota School of Mines and Technology, Stanford University, University of Wisconsin–Madison, University of Oklahoma, University of California, Davis, Sanford Research
Language: English
Subfield: Fuel Technology
Field: Energy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,500
Awards: G11630931, G125460123, G14554683, G42916606
OpenAlex ID: W3179536620