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Wastewater Disposal and Hydraulic Fracturing Interaction Propagating Seismicity in Oklahoma

Description: 

Wastewater injection and hydraulic fracturing processes have independently been attributed to induced seismicity in Oklahoma. When the two processes occur concurrently in close spatial proximity, an interaction of the perturbed stress can accelerate slip, inducing seismicity on a fault. We analyze a sequence in eastern Oklahoma, near the town of Quinton, where an earthquake sequence occurred over a several year timespans in 2019-2022, adjacent to hydraulically-fractured well completions and a large volume injection well. We use this insight to better understand the interaction between wastewater injection and hydraulic fracturing processes and evaluate their respective roles in inducing earthquakes. We analyze the frequency content of the broadband seismograms to detect possible fluid movement on the seismogenic faults by analyzing waveforms recorded at the same station to discount the influence of the ray path and site conditions. Analysis of the energy frequency spectrum (i.e., frequency index) indicates a temporal variation of frequencies that has increasingly low frequency events correlated with times of active wastewater injection. The increasing low frequency content events coincides with an increased rate of seismicity. Upon the cessation of injection, the low frequency content in events decreases over time as the seismicity rate decreases. Constrained earthquake focal depths from a relocated catalog indicate that the low frequency earthquakes occur only within the sedimentary formations along with the high frequency dominated earthquakes, even though the later extends into the basement. We postulate the hydraulic fracturing process reactivates faults that are hydraulically connected to the wastewater injection well that subsequently allow fluid propagation into the seismogenic faults, as observed from the spatiotemporal distribution of the earthquakes. We conducted lab experiments for different earthquake excitation scenario for faults saturated with fluid and compare to semi-saturated faults. We will present an updated analysis of simulation of earthquake excitation on faults with variable fluid content.

Session: Induced Earthquakes: Source Characteristics, Mechanisms, Stress Field Modeling and Hazards [Poster Session]

Type: Poster

Date: 5/1/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Paul

Student Presenter: No

Invited Presentation: 

Authors