(Updates with Cuadrilla comments from fourth paragraph.)
Nov. 2 (Bloomberg) -- Two small earthquakes near Blackpool in northwest England earlier this year were probably caused by hydraulic fracturing, a technique of grinding underground rocks to extract natural gas.
It’s “highly probable” that fracking, as the process is known, at the Preese Hall-1 site caused the quakes, U.K.-based shale explorer Cuadrilla Resources Ltd. said in a report published today. The geological circumstances were “rare” and the strongest possible tremor, of a magnitude of 3, wouldn’t be a risk to safety or property on the surface, it said.
Still, the findings may add to concern that fracturing is harmful to the environment and slow the technology’s development in Britain. While fracking has made the U.S. the world’s largest gas producer, France has halted the practice for fear it may pollute drinking water. The process involves injecting rock with sand and chemical solution to release the gas.
Cuadrilla estimates the reserves found near Blackpool may hold enough gas to meet U.K. demand for a year and a half. The company plans to continue fracking after the authorities have reviewed the report, which may take 30 to 60 days, Chief Executive Officer Mark Miller said today.
Early Warning System
“The report showed the pumping operations we were involved in triggered the events,” Miller said in a telephone interview. “It also gave us recommendations for how to proceed that will mitigate that risk. We can change the volume of the fluids as well as put in an early warning system that would give us the ability to terminate drilling very early.”
Cuadrilla halted operations earlier this year after two tremors were felt on the surface. The first, on April 1, measured 2.3 on the Richter scale and another on May 27 measured 1.5. Homeowners in the seaside resort of Blackpool called the police after feeling their houses shake, the British Broadcasting Corp. reported.
Pressure from fluids on a so-called stressed fault zone probably caused the quakes, the report showed. It’s unlikely other wells in the basin will breach similar areas, it said.
Protesters from Frack Off, a group protesting against shale drilling, entered one of Cuadrilla’s sites today and stopped its other drilling operations, Miller said.
--With assistance from Ben Farey in London. Editors: Will Kennedy, Amanda Jordan
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