For the second time in two weeks since Cuadrilla started fracking at an exploration site in northwest England-resuming hydraulic fracturing in the UK for the first time in seven years-the company had to stop operations on Monday due to a micro seismic event measuring above the threshold requiring a halt.
Cuadrilla confirmed that a micro seismic event measuring 1.1 on the Richter scale was detected at about 11.30 a.m. local time on Monday, while the team were hydraulically fracturing at the Preston New Road shale gas exploration site in Lancashire, the company said in a statement today.
According to regulations, in case of micro seismic events of 0.50 on the Richter scale or higher, fracking must temporarily be halted and pressure in the well reduced.
"This is the latest micro seismic event to be detected by the organisation's highly sophisticated monitoring systems and verified by the British Geological Survey (BGS). This will be classed as a 'red' event as part of the traffic light system operated by the Oil and Gas Authority but as we have said many times this level is way below anything that can be felt at surface and a very long way from anything that would cause damage or harm," Cuadrilla said.
"Well integrity has been checked and verified," the company said, noting that in line with regulations, fracking has paused for 18 hours.
Cuadrilla had paused fracking at the site on Friday morning after a 0.76 on the Richter scale micro seismic event was recorded, the latest of some dozen seismic events since fracking started, but the first that was above the 0.5 threshold.
The seismic event on Monday was the strongest yet to be recorded since Cuadrilla started fracking at the exploration site two weeks ago, on October 15.
Anti-fracking activists say that there have been now 27 seismic events since October 15, Blackpool Gazzette reports.
By Tsvetana Paraskova for Oilprice.com
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