Knowns, questions, and implications of induced seismicity in the Permian Basin

Dr. Sakharov: Induced seismicity remains a pressing concern for the Permian Basin and other wastewater injection regions, including, inter alia, Oklahoma. While the Permian has seen a staggering 45 billion barrels of wastewater injected since 2009, similar risks are present in Oklahoma, given its complex fault networks and history of seismic events.

For operators planning water flowback to extract critical minerals like iodine and lithium, there is an additional layer of complexity. Extracting previously injected water can alter subsurface pressures unevenly, posing a risk of reactivating faults already weakened by historical injection. This highlights the need for detailed geomechanical modeling and pressure monitoring prior to flowback operations.

Additionally, orphan wells present both a challenge and an opportunity. Before plugging and abandoning these wells, controlled depressurization of the reservoir through managed extraction could reduce fault slip potential, mitigate seismic risks, and simultaneously unlock value via mineral recovery.

The Permian Basin and Oklahoma share the challenge of balancing hydrocarbon production, wastewater management, and seismic mitigation. Modern technologies, such as advanced subsurface imaging, pressure management systems, and continuous seismic monitoring, are essential to ensure safe and sustainable operations while exploring innovative solutions for critical mineral extraction.

Abstract

Unconventional hydrocarbon development in the Permian Basin has required disposal of approximately 45 billion bbl of coproduced wastewater since 2009. This injection has altered subsurface stress and caused the widespread development of earthquakes on preexisting faults. Earthquakes have also been triggered by hydraulic fracturing in some areas. The induced earthquakes have caused general concern and regulatory actions that challenge the sustainability of current wastewater disposal practices. Much has been learned about the nature of the induced seismicity in the Permian Basin from academic research and industry collaboration. Many questions persist.

Induced seismicity in the Permian Basin occurs in seven regions and two general stratigraphic levels and is driven by four processes. The greatest concern comes from wastewater injection between the productive shale intervals and basement causing rupture on basement-rooted faults with local magnitudes as high as ML5.4. Induced seismicity on the most sensitive faults has occurred as distant as 40 km from deep injection. Wastewater injection above the productive shales, hydraulic fracturing, and differential depletion of shale reservoirs have contributed to the seismicity but are associated with smaller maximum magnitudes (≤ML3.5) to date.

Responding to the seismicity, petroleum regulators in Texas and New Mexico and operators of injection wells collaborated to reduce the rate of injection into deep strata beginning in late 2021, leading to a reduction in the rate of cataloged earthquakes and indicating that retroactive mitigation works in reducing the seismic hazard. Research into the causes and mechanisms of induced seismicity in the Permian Basin has served to underpin mitigation approaches.

(Dr. Sakharov: Unfortunately, I don't have an access to the publication itself. It can be bought here if you have money-honey.)