Posted on November 15, 2013 by Dean Calland
New rumblings are being heard regarding carbon sequestration. Proponents of the injection of substances into deep formations as a desirable method of waste disposal were shaken to learn that a study published just this week has concluded that the underground injection of carbon dioxide in Texas may have induced earthquakes. This follows on the heels of a much publicized study performed for the Ohio Department of Natural Resources (ODNR) last year that concluded that the injection of oil field brine into an underground injection well (known as the Northstar 1 Well) near Youngstown, Ohio, was at fault for inducing seismic activity.
The potential for causing earthquakes from CO2 injection has sent tremors through the clean coal (or perhaps “green coal”) camps. Injection bans or significant regulatory hurdles that reduce the availability of injection could create severe aftershocks for the fossil fuel industry. Affordable capture and underground storage of CO2 is a significant potential opportunity in the clean coal industry’s plan to extend the useful lives of coal burning industrial facilities.
Fortunately, both the Texas and Ohio studies suggest that the circumstances in which injection induces seismic activity are uncommon, although a number of citizen groups may not agree with this assessment. Ohio’s experience with the underground injection of oil and gas waste fluids may predict how this will play out at the national level. Beginning in March 2011, an area near the Northstar 1 Well experienced twelve minor earthquakes. The State of Ohio began an evaluation, ordered the well and four nearby injection wells to cease operations, and discontinued issuing permits for new UIC wells. ODNR concluded that injection in the Northstar 1 Well had indeed induced the earthquakes, but they resulted from injections into the “basement” Precambrian formation that had a pre-existing fault that was likely in a near-failure state at the time of the injections.
The Texas study on CO2 published this week by the Proceedings of the National Academy of Sciences examined small earthquakes that occurred in 2009 through 2011 in a large oil and gas field in northwest Texas. Operators in the area had been injecting CO2 to enhance oil recovery since 1971, and significantly increased injections in one of the fields, the Cogdell field, in 2004. A temporary network of seismometers detected 93 earthquakes in the Cogdell field from March 2009 to December 2010. However, no seismic activity was detected in nearby injection areas, causing the authors of the study to conclude that seismic activity is likely to occur only in areas with geological faults that are unstable at the time of injection. Thus, there is not much of a gap between the findings of the Texas and Ohio studies.
This issue is likely to create an even wider fissure between clean coal supporters and environmental groups, although future studies will likely determine if this debate grows to seismic proportions.