The increase in seismic activity in the south central US over the past decade is believed by many to be caused by the oil and gas industry. Organizations such as the USGS believe that produced water disposal activities are the primary cause of the spike in earthquakes. Oklahoma has seen over 3,000 Magnitude 3.0 earthquakes recorded between 2009 and August 2018, with a corresponding increase in saltwater disposal (SWD) activities in the state. Similar trends have been observed in Texas and southern New Mexico. State agencies are scrutinizing disposal activities in quake-prone regions and limiting injection pressures and volumes for SWD wells.
ESG Solutions offers Induced Seismic Monitoring (ISM) solutions that incorporate near-surface arrays of low-frequency, broadband seismometers and digital recorders that passively monitor microseismic activity during SWD operations. This real-time monitoring helps operators optimize their injection rates, reduce the risk of suspending operations, and maintain a social license to operate near neighboring communities. Passive monitoring can help operators avoid larger events and costlier challenges to their SWD operations. By monitoring today and putting processes in place to limit induced seismicity, SWD operations will be positioned to run more efficiently, profitably, and in compliance with any future regulations.
The past decade has seen a dramatic jump in seismic activity in the south central US—and many people are pointing their fingers at the oil and gas industry. Is the uptick in hydraulic fracturing and saltwater disposal (SWD) operations in the Permian basin inducing seismic events, even many miles away?
While the jury is still out, organizations like the USGS are calling produced water disposal activities the primary cause of the recent spike in earthquakes in the central United States.
Oklahoma has become ground zero for much of this earthquake activity, with more than 3,000 Magnitude 3.0 earthquakes recorded between 2009 and August 2018. During that same time, SWD activities climbed dramatically in the state. And as more produced water was pumped into disposal wells, research suggests that the resulting stresses building up in the surrounding formation induced seismicity up to 10 miles away and at great depths. Similar cause-and-effect trends between SWD and induced seismicity are being observed in Texas and southern New Mexico.
State agencies in charge of issuing SWD permits are scrutinizing disposal activities in quake-prone regions. The Oklahoma Corporate Commission has developed a “traffic light” system that limits injection pressures and volumes for SWD wells. And in Texas, the state’s Railroad Commission can start reviewing an SWD operator’s activities if a Magnitude 2.0 event occurs.
Listening to the subsurface keeps seismic events in check
If you’re an SWD operator, do you understand how your operations impact the subsurface? What are the odds that your operations will induce seismic events that might force you to limit injection rates or stop injecting altogether?
Induced Seismic Monitoring (ISM) from ESG Solutions can help you answer these questions. Our ISM solutions, which incorporate near-surface arrays of low-frequency, broadband seismometers and digital recorders, passively monitor microseismic activity during your SWD operations. This real-time monitoring gives you the insights you need to optimize your injection rates, reduce the risk of suspending your operations, and maintain a social license to operate near neighboring communities.
Of course, you can’t achieve these goals without first understanding where you’re starting from. That’s why we install customized microseismic arrays—ideally months before the start of your SWD operation—to establish the background level of naturally occurring seismicity in your site’s subsurface.
With this background seismicity as a baseline, we continue monitoring microseismic events during your ongoing water injection operation. We also work with you to set up a critical alert notification system, which is typically a traffic light-style system with your own predetermined set points corresponding to different magnitude ranges.
If the number or magnitude of seismic events increases beyond a given set point, the system automatically alerts your operations team. An early-warning event corresponding to a yellow-light warning of Magnitude 1.5, for example, might prompt you to throttle back your injection rate and monitor the situation to see if the level of seismic activity dropped back down to baseline levels.
Passive monitoring pays off
Using our ISM solution to respond to seismic events earlier can help you avoid larger events and costlier challenges to your SWD operation. For example, a red-light-level warning (such as a Magnitude 2.0) would likely prompt a more serious response such as suspending operations, working to understand exactly what happened, and then taking steps to safely resolve the issue to resume injection.
When you consider the lost revenue and the potential for fines from regulatory authorities, a shutdown of even a few days can be more expensive than a full year of passive microseismic monitoring. And even if your SWD operation is not so strictly regulated today, that could change in the years ahead. But by monitoring today, and putting processes in place to limit induced seismicity, your operation will be positioned to run more efficiently, profitably, and in compliance with any future regulations.
In some states, continuous passive microseismic monitoring can help you amend your SWD permits for more profitable operations. In Texas for example, several SWD operators implementing our ISM solution have established a solid understanding of their baseline seismic activity and demonstrated due diligence in identifying and responding to abnormal seismic events. They’ve been able to show that higher injection rates in their wells do not lead to more severe seismic events. As a result, they’ve been permitted to operate their wells at higher injection rates and pressures.
ESG Solutions’ ISM arrays currently monitor half of Oklahoma, one-third of the Permian basin, and much of east Texas. Recently, we’ve implemented induced seismic monitoring in Oman and India. Several users are implementing our ISM service through a subscription-based, multiuser array model in which they pay a fee to access passive microseismic data. This model is a real time and money saver, giving clients the subsurface data they need to optimize their operations, but without the costs of installing and maintaining the monitoring equipment on their own site.
Want to learn how ESG Solutions can help optimize your SWD injection operations and keep you compliant with tightening regulations? Contact us today.