CO₂ Injection May Lead To Earthquakes

A recent study finds that injection of carbon dioxide into oil fields could lead to significant earthquakes. The study, published last week, raises concerns about underground injection and storage of supercritical CO₂ captured from coal- and gas-fired power plants (Proc. Natl. Acad. Sci. USA 2013, DOI: 10.1073/pnas.1311316110). The CO₂ injection could be used either for carbon sequestration or for enhanced oil recovery on depleted oil fields. Researchers compared a series of earthquakes that occurred in the Cogdell oil field near Snyder, Texas, between 2006 and 2011 with a previous set that occurred between 1975 and 1982. A prior analysis concluded that water injection led to the earlier earthquakes, but since 2004, the largest volume of oil-field injections was made up of gas, including CO₂. The researchers suggest that the gas injection is what led to as many as 18 recent large earthquakes. They stress that their results are preliminary and more study is needed. But if the injections triggered the recent seismicity, the researchers note, they would represent one of the only instances in which gas injection has resulted in earthquakes with a magnitude of 3.0 or larger.