Geology topics

Matthew Weingarten

Publications and source records attributed to Matthew Weingarten.

4 recordsLinked to original sources

USGS2016

Far-field pressurization likely caused one of the largest injection induced earthquakes by reactivating a large pre-existing basement fault structure

The M w 5.1 Fairview, Oklahoma, earthquake on 13 February 2016 and its associated seismicity produced the largest moment release in the central and eastern United States since the 2011 M w 5.7 Prague, Oklahoma, earthquake sequence and is one of the largest earthquakes potentially linked to wastewater injection. This energetic sequence has produced five earthquakes with M w 4.4 or larger. Almost all of these earthquakes occur in Precambrian basement on a partially unmapped 14 km long fault. Regional injection into the Arbuckle Group increased approximately sevenfold in the 36 months prior to the start of the sequence (January 2015). We suggest far-field pressurization from clustered, high-rate wells greater than 12 km from this sequence induced these earthquakes. As compared to the Fairview sequence, seismicity is diffuse near high-rate wells, where pressure changes are expected to be largest. This points to the critical role that preexisting faults play in the occurrence of large induced earthquakes.

Geophysical Research Letters↗

USGS2016

Rapid response, monitoring, and mitigation of induced seismicity near Greeley, Colorado

On 1 June 2014 (03:35 UTC), an M w 3.2 earthquake occurred in Weld County, Colorado, a historically aseismic area of the Denver–Julesburg basin. Weld County is a prominent area of oil and gas development, including many high‐rate class II wastewater injection wells. In the days following the earthquake, the University of Colorado, with support from the U.S. Geological Survey and Incorporated Research Institutions for Seismology–Portable Array Seismic Studies of the Continental Lithosphere, rapidly deployed six seismic stations to characterize the seismicity associated with the 1 June earthquake (the Greeley sequence) and to investigate its possible connection to wastewater disposal. The spatial and temporal proximity of earthquakes to a high‐rate wastewater disposal well strongly suggests these earthquakes were induced. Scientific communication between the university, state agencies, and the energy industry led to rapid mitigation strategies to reduce the occurrence of further earthquakes. Mitigation efforts included implementing a temporary moratorium on injection at the well, cementing the bottom portion of the disposal well to minimize hydrologic connectivity between the disposal formation and the underlying crystalline basement, and subsequently allowing injection to resume at lower rates. Following the resumption of wastewater disposal, microseismicity was closely monitored for both increases in earthquake rate and magnitude. Following mitigation efforts, between 13 August 2014 and 29 December 2015, no earthquakes larger than M 1.5 occurred near the Greeley sequence. This study demonstrates that a detailed and rapid characterization of a seismic sequence in space and time relative to disposal, combined with collaboration and communication between scientists, regulators, and industry, can lead to objective and actionable mitigation efforts that potentially reduced the rate of earthquakes and the possible generation of larger earthquakes.

Colorado↗

USGS2015

High-rate injection is associated with the increase in U.S. mid-continent seismicity

An unprecedented increase in earthquakes in the U.S. mid-continent began in 2009. Many of these earthquakes have been documented as induced by wastewater injection. We examine the relationship between wastewater injection and U.S. mid-continent seismicity using a newly assembled injection well database for the central and eastern United States. We find that the entire increase in earthquake rate is associated with fluid injection wells. High-rate injection wells (>300,000 barrels per month) are much more likely to be associated with earthquakes than lower-rate wells. At the scale of our study, a well’s cumulative injected volume, monthly wellhead pressure, depth, and proximity to crystalline basement do not strongly correlate with earthquake association. Managing injection rates may be a useful tool to minimize the likelihood of induced earthquakes.

Science↗

USGS2014

Sharp increase in central Oklahoma seismicity 2009-2014 induced by massive wastewater injection

Unconventional oil and gas production provides a rapidly growing energy source; however high-producing states in the United States, such as Oklahoma, face sharply rising numbers of earthquakes. Subsurface pressure data required to unequivocally link earthquakes to injection are rarely accessible. Here we use seismicity and hydrogeological models to show that distant fluid migration from high-rate disposal wells in Oklahoma is likely responsible for the largest swarm. Earthquake hypocenters occur within disposal formations and upper-basement, between 2-5 km depth. The modeled fluid pressure perturbation propagates throughout the same depth range and tracks earthquakes to distances of 35 km, with a triggering threshold of ~0.07 MPa. Although thousands of disposal wells may operate aseismically, four of the highest-rate wells likely induced 20% of 2008-2013 central US seismicity.

Oklahoma↗