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Multidisciplinary Approach to Identify and Mitigate the Hazard from Induced Seismicity in Oklahoma

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Multidisciplinary Approach to Identify and Mitigate the Hazard from Induced Seismicity in Oklahoma Multidisciplinary Approach to Identify and Mitigate the Hazard from Induced Seismicity in Oklahoma Aus$n Holland, Randy Keller, Amberlee Darold, Kyle Murray, Steve Holloway, Kevin Crain Acknowledgements Industry contributors to RPSEA and fault database Oklahoma Independent Petroleum Associa8on (OIPA) USGS – providing many Oklahoma Secretary of Energy and Environment different temporary Oklahoma Corpora8on Commission seismic staons OU Mewbourne College of Earth and Energy Oklahoma’s Increase in Earthquakes Earthquake rates per year Magnitude 4 or Greater Magnitude 3 or Greater Earthquakes Earthquakes Years 1980-2008 0.1 1.6 20 Year 2009 3 42 Years 67 Year 2010 1882-2008 40 Years Year 2011 2009-2013 427 109 Year 2014 Year 2012 24 Year 2013 Updated Oct. 20, 2014 Year 2014 Earthquake Forecasting • Probability of one or more earthquakes of magnitude (m) over the sPecified $me • Not a Predic$on, but a forecast Oklahoma Recurrence Rates & Probabilities Mc=1.9 Mc=2.3 Calculated with a 6 month moving window Oklahoma Earthquakes 2009-2014 Area of greatest increase is about 15% of Oklahoma. Captures areas of significant waste-water disPosal wells Cumulative Seismicity in Oklahoma Cumula8ve Number of Earthquakes Oklahoma Geol. Survey www.okgeosurvey1.gov/Pages/earthquakes/catalogs.PhP UIC Class II Injection Oklahoma Earthquakes 2009-2014 Area of greatest increase is about 15% of Oklahoma. Captures areas of significant waste-water disPosal wells RPSEA - 4D Integrated Multi-scale Reservoir and Geological Modeling • 4D geoPhysical monitoring • Localized well-based Pressure tests • Goals – ImProve model Predic$ve capabili$es – Maintain a suite of Progressively uPdated models – ImProved rePresentaon of the Preferen$al flowPaths – Geomechanical ProPer$es and fault characteris$cs in the subsurface OKRaH Seismic Network 3D geologic and geophysical model • 100,000’s of Wells in central Oklahoma • Geological and geoPhysical logs combined to build 3D models GeosPaally referenced surfaces Hunton • IncorPorated (orange) and basement (brown). into 3D seismic Geologic units are assigned Physical ProPer$es velocity models such as from well logs with sPaally varying ProPer$es such as Permeability, density, Porosity, and velocity. Gravity Observations Provide Constraints on Geologic Models Industry Contribu$ng to Enhanced Fault Database All Submitted Faults Interagency Cooperation Industry, OCC UIC DOE and Data OGS Program State of OK SuPPort OP$mally Oriented Faults Fault Maps Industry Fault Fault Database Database Earthquake Project Informaon Contributors & OIPA New Permit & Earthquake ImProvements to Monitoring and Seismograph Exis$ng Permits RePor$ng Network Reservoir & Injec$on and Geomechanical OPeraonal Data Addi$onal Studies Modeling RPSEA Current Mitigation Steps • Oklahoma CorPoraon Commission is the regulator of UIC Class II wells, and have imPlemented different mi$gaon strategies – New rules regarding rePor$ng of injec$on volumes and Pressures in the “Arbuckle” – Permit modificaons; i.e. “Traffic Light System” – Enhanced rePor$ng requirements in OCC areas of interest, currently 10 km around ML 4+ earthquakes • Not required by rule for non-Arbuckle wells, but oPerators have comPlied for requests of greater rePor$ng – New Permits are checked against fault maps and background seismicity Summary • The rate of seismicity has increased dramacally and so has the seismic hazard • Building large geological and geoPhysical data sets at varying scales and dimensions • Con$nue to Provide data Products to stakeholders and iden$fying new data sources • A greater understanding of Physical Processes in Oklahoma will helP to inform future mi$gaon strategies • Mul$-agency cooPeraon has now been solidified in the governor’s Coordinang Council Abstract Oklahoma has exPerienced a very significant increase in seismicity rates over the last 5 years with the greatest increase occurring in 2014. The observed rate increase indicates that the seismic hazard for at least some Parts of Oklahoma has increased significantly. Many seismologists consider the large number of salt-water disPosal wells oPerang in Oklahoma as the largest contribu$ng factor to this increase. However, unlike many cases of seismicity induced by injec$on, the greatest increase is occurring over a very large area, about 15% of the state. There are more than 3,000 disPosal wells currently oPerang within Oklahoma along with injec$on volumes greater than 2010 rates. These factors add many significant challenges to iden$fying Poten$al cases of induced seismicity and understanding the contribu$ng factors well enough to mi$gate such occurrences. In resPonse to a clear need for a bener geotechnical understanding of what is occurring in Oklahoma, a mul$-year mul$disciPlinary study some of the most ac$ve areas has begun at the University of Oklahoma. This study includes addi$onal seismic monitoring, bener geological and geoPhysical characterizaon of the subsurface, hydrological and reservoir modeling, and geomechanical studies to bener understand the rise in seismicity rates. The Oklahoma CorPoraon Commission has added new rules regarding rePor$ng and monitoring of salt- water disPosal wells, and con$nue to work with the Oklahoma Geological Survey and other researchers. .
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