As information continues to mature around potential links between induced seismicity and underground injection of waste water or hydraulic fracturing, we incorporate this knowledge into our risk management program. We're a leader in determining and employing risk mitigation strategies such as seismic reviews of disposal wells, minimizing use of disposal wells in sensitive geologic areas, participating in area-wide arrays and using temporary seismometers when necessary during hydraulic fracturing.
In 2020, our company-wide seismicity program was integrated into ROMS, further advancing our systematic approach to mitigating seismic risk. Seismic risk and its potential causes are generally related to local geologic conditions requiring a tailored approach for mitigation. While seismic events are rare in North Dakota, all unconventional assets are included in the program, which is designed to apply the appropriate analysis and mitigation procedures to local conditions. Company subject-matter experts share our learnings with other operators and industry organizations to increase industry-wide capacity to prevent and minimize induced seismicity.
We support scientific research into links between seismicity and oil and gas activity, as well as regulatory oversight and information sharing to prevent and mitigate seismic activity potentially connected to our operations.
Marathon Oil sponsors or supports academic organizations and government agencies involved in research into seismicity and oil and gas operations, such as the Center for Integrated Seismicity Research (CISR) at the University of Texas at Austin, a collaborative that collects high-quality data on earthquakes in Texas and conducts fundamental and applied research to better understand naturally occurring and potentially induced earthquakes and the associated risks. Historically, we’ve also supported the Stanford Center for Induced and Triggered Seismicity, and helped establish the Oklahoma Corporation Commission (OCC) rules. We also work collaboratively with trade associations, including the Texas Oil and Gas Association and The Petroleum Alliance of Oklahoma’s seismic subcommittees and the Permian Basin Petroleum Association.
Preventing Seismic Activity
Most injection wells aren’t associated with felt earthquakes, according to the USGS, which has found that a combination of many factors is necessary for injection to contribute to earthquakes that can be felt rather than measured. Generally, the magnitude required for a person to feel seismic activity is ~2.5. In general, there is considerable natural seismic activity that goes unnoticed below this level, but is measurable using technology.
We take precautions to prevent disposal of produced water from our sites into wells/areas where we’ve identified an increased risk of salt water injection induced seismicity due to geologic conditions or historical seismic activity. Risk analysis associated with injection well disposal is managed through our ROMS system with documentation and site approval through our Waste Management and Vetting Approval Process. Use of our electronic transportation management system for waste haulers allows for adherence verification that our waste is transported to approved sites.
While seismicity associated with completion activity is rare, we monitor our completion sites in areas of concern to mitigate seismic activity through participation in a multi-operator, area-wide seismic array. Initiating mitigation activities promptly reduces the severity of seismic activity that may be associated with well stimulation. Marathon Oil’s mitigation protocols exceed regulatory requirements in the areas where we operate.
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