The heated debate about fracking began relatively recently in the UK, but the roots of the technique can be dated back to the 1860s.
Here is a brief history of fracking – properly known as hydraulic fracturing – and its use in the UK.
The origins of fracking
The roots of modern fracking can be traced back to American Civil War veteran Edward Roberts receiving a patent for an “exploding torpedo” in April 1865, which was detonated in oil wells to increase production.
The first experimental use of hydraulic fracturing was in the US in 1947, but it was not until hydraulic fracturing was combined with advances in horizontal drilling that the modern method was born.
Fracking in the UK
According to the National Audit Office (NAO) fracking has been used to extract oil and gas from offshore and onshore reserves in the UK since the 1970s.
A report from the Royal Society and Royal Academy of Engineering in 2012 said the UK had used hydraulic fracturing and directional drilling for non-shale gas applications, with around 200 onshore wells having been hydraulically fractured during the previous 30 years.
In 2003, the Petroleum Revenue Act was repealed, exempting shale gas production from the petroleum revenue tax.
In 2008, 97 petroleum exploration and development licences were awarded for shale gas exploration in the UK.
By June 2012, Cuadrilla had identified five potential shale gas exploration well sites in Lancashire and the first test well was drilled in August 2010 at Preese Hall, the report said.
A second test was carried out at Grange Hill Farm later that year, and a third near the village of Banks in August 2011.
Fracking and earthquakes
Cuadrilla stopped fracking its Preese Hall well in 2011 after detecting an earthquake of 2.3 local magnitude (ML) and up to 1.5ML in ensuing tremors, the NAO said.
The Government then put in place a moratorium on fracking, which was lifted in December 2012.
Cuadrilla fracked a second well in late 2018, recording six earthquakes above 0.5ML – with the highest reaching 1.5ML, according to an NAO report.
In August 2019, the operator suspended its fracking activity at a third well after inducing earthquakes of 1.6ML, 2.1ML and 2.9ML over the course of five days.
By October 2019 three wells in Lancashire had been fracked by Cuadrilla, the NAO said.