Thumbnail.jpgEarth magazine’s Carolyn Gramling interviewed SMU geophysicist Brian Stump about the operation of a saltwater injection disposal well that was a “plausible cause” for a series of small earthquakes in the Dallas-Fort Worth area in 2008.

The May 13 article in Earth, the magazine of The American Geological Institute, explores the research into the earthquakes, which occurred in an area of North Texas where the vast Barnett Shale geological formation traps natural gas deposits in subsurface rock.

Natural gas production in the Barnett Shale relies on the injection of pressurized water into the ground to crack open the gas-bearing rock, a process known as “hydraulic fracturing.”

Some of the injected water is recovered with the produced gas in the form of waste fluids that require disposal. Research by Stump looked at incidents that occurred in an area of North Texas where the vast Barnett Shale geological formation traps natural gas deposits in subsurface rock.

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By Carolyn Gramling
Earth Web Editor, Reporter

A saltwater disposal well, a part of the natural gas production process, may have been responsible for triggering a series of minor earthquakes in the Dallas-Fort Worth area of Texas in 2008, according to a recent study.

A series of small earthquakes that shook up the Dallas-Fort Worth area may be linked to natural gas production in the nearby Barnett Shale.

From Oct. 31 to Nov. 1, 2008, several minor earthquakes rattled the walls and shook the furniture of numerous residences in the Dallas-Fort Worth area.

The earthquakes, with magnitudes between 2.5 and 3.0, prompted questions among the residents about whether drilling for natural gas in the nearby Barnett Shale was responsible for the shaking. A second series of earthquakes, with the largest a magnitude 3.3, occurred on May 16, 2009; a third occurred on June 2, 2009.

Natural gas production involves multiple steps, including drilling a natural gas well, pumping pressurized fluids into the well to crack open the rock (hydraulic fracturing), and then extracting the natural gas and used fluids.

Once the gas and fluids are extracted, the fluids are reinjected back into the ground via a different well, called a saltwater disposal well, located some distance away from the production wells.

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Related links:
Barnett Shale
hydraulic fracturing
33TV: Five earthquakes in one week
DMN: SMU deploys seismic stations to Cleburne
Brian Stump
Brian Stump and Chris Hayward
Texas Bureau of Economic Geology
USGS National Earthquake Information Center