A new study study points carbon dioxide injected in wells as the cause of the minor earthquakes in Texas. It is the first one to link oil recovery measures to increased seismic movement in Texas.
Carbon dioxide is usually injected in oil wells to improve production of oil. This is a common oil recovery technique used in old oil grounds like the Cogdell field, which is just one of the 7,000 oil areas in the West Texas’ Permian Basin.
According to Reuters, most oil companies use carbon dioxide comprehensively in their oil recovery projects in the area. For instance, the oil corporation Occidental Petroleum details in its website that around 60 percent of its oil yield in West Texas and southeast New Mexico were produced with significant help from extensive carbon dioxide injections.
The researchers led by Wei Gan Beijing’s China University of Geosciences investigated 93 earthquakes within the period March 2009 to December 2010. They also obtained data from the USArray program’s six makeshift seismograph stations. Their analysis revealed that there seem to have apparent links to the seismic rumbles which are magnitude 3 and above with the carbon dioxide flooding in the Cogdell area nearby Snyder, Texas.
Before these quakes, within the period 1975 to 1982, the earthquakes were associated to water injections in the wells. The researchers say that this explanation is not applicable to the more recent seismic events but instead is caused by carbon dioxide flooding.
According to the study, "The timing of gas injection suggests it may have contributed to triggering the recent seismic activity. If so, this represents an instance where gas injection has triggered earthquakes having magnitudes 3 and larger."
Other studies in recent years associated wastewater disposal and fracking wells to more frequent earthquakes especially in the northern part of Texas and central part of Oklahoma.
The study collaborated by Wei Gan of Beijing’s China University of Geosciences and Cliff Frohlich Austin’s University of Texas was published in the Proceedings of the National Academy of Sciences.
