Published on June 18th, 2012 | by Joshua S Hill0
Oil and Conventional Gas Extraction Can Cause Earthquakes Too
There has been a lot of controversy around the question ‘does hydraulic fracturing of shale to release natural gas cause earthquakes‘. Geologists and politicians have butted heads, unsurprisingly, when scientific fact gets in the way of environmental and energy policy. A new study has found again, however, that yes, fracking does indeed cause earthquakes. However, it doesn’t cause as many earthquakes as conventional extraction of oil and natural gas.
The comprehensive study, released Friday by the National Research Council and entitled “Induced Seismicity Potential in Energy Technologies,” documented earthquakes associated with a full range of underground energy technologies, including conventional oil and gas wells, geothermal energy, enhanced geothermal, and carbon sequestration. The researchers found that there was a higher rate of quake when those wells were somewhat drained and injected with water or gas to force the remaining contents back up.
In fact, the greatest risk of earthquake does not come as a result of drilling into the earth, or cracking it with pressurised water and chemicals, but rather when the wastewater from those operations is pumped back down into deep sandstone or other formations for permanent disposal, instead of storing it topside.
Wastewater injection is believed to be responsible for earthquakes that took place in Youngstown, Ohio, on Christmas Eve and again on New Year’s Eve, measuring 2.7 and 4.0 on the Richter scale respectively.
The report found that technologies aimed at balancing the amount of fluid removed or injected — such as conventional oil wells — induced fewer earthquakes than those that involve net injection of extraction.
“The two techniques with the largest imbalance are carbon sequestration and wastewater injection,” said Murray Hitzman, professor of economic geology at the Colorado School of Mines and chairman of the committee that wrote the report, at a press briefing today. The two techniques increase subsurface pressure across large areas, so there is a greater chance of running across a fault, which could lead to an earthquake, Hitzman said.
What the committee was most troubled by was the almost complete lack of industry “best practices” for minimising the risk of earthquakes. They strongly recommend that energy companies work with the U.S. Department of Energy to establish a set of “best practices” to minimise the likelihood of further earthquakes.
Source: Scientific American
Image Source: National Research Council