TY - JOUR
T1 - Joint focal mechanism inversion using downhole and surface monitoring at the decatur, illinois, co2 injection site
AU - Langet, Nadège
AU - Goertz-Allmann, Bettina
AU - Oye, Volker
AU - Bauer, Robert A.
AU - Williams-Stroud, Sherilyn
AU - Dichiarante, Anna Maria
AU - Greenberg, Sallie E.
N1 - Funding Information:
Data are provided by the Midwest Geological Sequestration Consortium (MGSC). The Illinois Basin - Decatur project (IBDP) is a public–private partnership among government agencies, private companies, consultancies, and research organizations. Data used to generate the results presented here are provided as supporting information and are available upon request. The facilities of Incorporated Research Institutions for Seismology (IRIS) Data Services, and specifically the IRIS Data Management Center, were used for access to the U.S. Geological Survey (USGS) waveforms and related metadata used in this study. IRIS Data Services are funded through the Seismological Facilities for the Advancement of Geoscience and EarthScope (SAGE) Proposal of the National Science Foundation under Cooperative Agreement EAR-1261681. The codes for computing the source mechanisms have been developed by the authors and are now part of Norwegian Seismic Array’s (NORSAR’s) internal microseismic data analysis software that was also used for general data processing as well as ray paths computation. The focal mechanism plots in Figures 8 and 10 used a modified version of the focalmech function from Conder (2020). The plot in Figure 11b is based on an open-source code written by Miroslav Hallo (Prague, Czech Republic). The unpublished manuscript is from S. Williams-Stroud, R. A. Bauer, H. Leetaru, V. Oye, F. Stanek, S. E. Greenberg, and N. Langet, 2020, Induced seismicity hazard from potential fault reactivation by injection during the Illinois Basin - Decatur Project, Bull.Seismol.Soc.Am. The supplemental material provides a more exhaustive description of the seismic network, of the 23 events used in the study (timing, magnitude, location including uncertainties) as well as a table containing the 1D velocity model.
Funding Information:
The authors are grateful for support through the Climit program of Gassnova Project Number 618233. The Midwest Geological Sequestration Consortium is funded by the U.S. Department of Energy through the National Energy Technology Laboratory (NETL) via the Regional Carbon Sequestration Partnership Program (Contract Number DE-FC26-05NT42588) and by a cost share agreement with the Illinois Department of Commerce and Economic Opportunity, Office of Coal Development through the Illinois Clean Coal Institute. The authors thank A. Wüstefeld, Norwegian Seismic Array (NORSAR), leading the initiative on internal software development used for the analysis, and all the colleagues contributing. The authors also thank Jan Šilený from the Institute of Geophysics of the Czech Academy of Sciences and J. Ole Kaven from the U.S. Geological Survey (USGS) for their useful comments, which helped improve the article.
Funding Information:
The authors are grateful for support through the Climit program of Gassnova Project Number 618233. The Midwest Geological Sequestration Consortium is funded by the U.S. Department of Energy through the National Energy Technology Laboratory (NETL) via the Regional Carbon Sequestration Partnership Program (Contract Number DE-FC26-05NT42588) and by a cost share agreement with the Illinois Department of Commerce and Economic Opportunity, Office of Coal Development through the Illinois Clean Coal Institute. The authors thank A. W?stefeld, Norwegian Seismic Array (NORSAR), leading the initiative on internal software development used for the analysis, and all the colleagues contributing. The authors also thank Jan ?ilen? from the Institute of Geophysics of the Czech Academy of Sciences and J. Ole Kaven from the U.S. Geological Survey (USGS) for their useful comments, which helped improve the article.
Publisher Copyright:
© Seismological Society of America.
PY - 2020/10/1
Y1 - 2020/10/1
N2 - The three-year CO2 injection period at the Illinois Basin-Decatur Project site (Decatur, Illinois, United States) produced a number of microseismic events distributed in very distinct spatiotemporal clusters with different orientations. Further characterization of the microseismicity encompasses the determination of the event source mechanisms. Initially, the microseismic monitoring network consisted solely of borehole sensors, but has been extended with surface sensors, thereby significantly improving the data coverage over the focal sphere. This article focuses on 23 events from the northernmost microseismic cluster (about 2 km from the injection point) and takes advantage of both, surface and downhole, recordings. The resulting strike-slip east–west-oriented focal planes are all consistent with the east–west orientation of the cluster in map view. The injection-related increase of pore pressure is far below the formation fracture pressure; however, small stress-field changes associated with the pore-pressure increase may reach as far as to the investigated cluster location. Monte Carlo modeling of the slip reactivation potential within this cluster showed that the observed maximum stress-field orientation of N068° is the optimum orientation for fault reactivation of the east–west-oriented cluster. Our results suggest that the east–west orientation of the investigated cluster is the main reason for its activation, even though the cluster is about 2 km away from the low-pressure injection point.
AB - The three-year CO2 injection period at the Illinois Basin-Decatur Project site (Decatur, Illinois, United States) produced a number of microseismic events distributed in very distinct spatiotemporal clusters with different orientations. Further characterization of the microseismicity encompasses the determination of the event source mechanisms. Initially, the microseismic monitoring network consisted solely of borehole sensors, but has been extended with surface sensors, thereby significantly improving the data coverage over the focal sphere. This article focuses on 23 events from the northernmost microseismic cluster (about 2 km from the injection point) and takes advantage of both, surface and downhole, recordings. The resulting strike-slip east–west-oriented focal planes are all consistent with the east–west orientation of the cluster in map view. The injection-related increase of pore pressure is far below the formation fracture pressure; however, small stress-field changes associated with the pore-pressure increase may reach as far as to the investigated cluster location. Monte Carlo modeling of the slip reactivation potential within this cluster showed that the observed maximum stress-field orientation of N068° is the optimum orientation for fault reactivation of the east–west-oriented cluster. Our results suggest that the east–west orientation of the investigated cluster is the main reason for its activation, even though the cluster is about 2 km away from the low-pressure injection point.
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U2 - 10.1785/0120200075
DO - 10.1785/0120200075
M3 - Article
AN - SCOPUS:85092029837
SN - 0037-1106
VL - 110
SP - 2168
EP - 2187
JO - Bulletin of the Seismological Society of America
JF - Bulletin of the Seismological Society of America
IS - 5
ER -