The big question last summer was whether the small earthquakes that popped up around D-FW Airport and Cleburne were linked to natural gas drilling activities in the Barnett Shale.
A team of researchers at SMU and the University of Texas has published a paper that concludes there's a link between the earthquakes and injection wells -- the high-pressure wells used to get rid of millions of gallons of wastewater produced by natural gas wells.
Caveats, according to SMU researcher Brian Stump: The team believes there's a correlation between the earthquakes at DFW airport and injection wells because the airport quakes seemed to be localized around an injection well at the airport. And the quakes stopped when the well was shut down.
But there's no evidence linking actual well-drilling or hydraulic fracturing to the quakes. And the jury is still out on the quakes in Cleburne. There are hundreds of injection wells in the Barnett Shale gas field, and thousands in Texas. Stump said the well at DFW airport is located next to an underground fault line.
Stump said there's definitely a need to do more studies, since a lot of proposed new energy sources like geothermal and "clean coal" power plants will require injecting gas or fluids underground.
The full report is available here: Earthquake-study-10march2010
There's a map on page 4 that shows the location of the airport, the injection well and the earthquakes.
UPDATE: Chesapeake fired back -- and hard -- saying that a "causal relationship . . . has not been scientifically proven."
Read below the jump for Chesapeake's statement -- and watch for the full story in tomorrow's Star-Telegram.
-- Mike Lee
Chesapeake appreciates the efforts of the scientists at SMU and UT Austin and agrees with their statement that natural gas drilling, hydraulic fracturing and production are not related to seismic activity near DFW International Airport. We believe this paragraph from their own paper adequately sums up our thoughts:
“More than 12,000 wells have been completed in the Barnett Shale of the Fort Worth Basin in the past decade and all received hydraulic fracture treatments. More than 200 saltwater disposal wells are active in the area of the Barnett production. If the DFW earthquakes were caused by saltwater injection or other activities associated with producing gas, it is puzzling why there are only one or two areas of felt seismicity,” according to their article published in Leading Edge.
Currently, there are more than 24,000 active injection wells in Texas, making the likelihood of a relationship between saltwater disposal wells and seismicity extremely rare. In addition, while residents of the area may not actually feel seismic events, they often occur. Between 1973 and 2007, there were 103 reported earthquakes in Texas. The 11 seismic events that SMU has recorded with their local network near the DFW Airport C1DE SWD well were too small to be felt. The USGS estimates that there are more than one million seismic events annually around the world like those of the size near DFW Airport. These seismic events have been described as a “vibration like passing of light trucks,” by UT researcher Cliff Frohlich in his book Texas Earthquakes.
Chesapeake maintains that a direct, causal relationship between saltwater disposal wells and seismic activity in the DFW area has not been scientifically proven.