Anti-fracking protesters have attempted to stop a gas drilling rig arriving at Barton Moss in Greater Manchester.
Police cleared the road to allow energy company IGas onto the site, between Barton Aerodrome and the M62.
A man, aged 41, from the Glossop area was arrested on suspicion of obstructing police and the road, said a police spokesman.
IGas confirmed plans to build a vertical test well at Barton Moss but said they have "no plans" for fracking.
Chief operating officer John Blaymires, said exploratory drilling is "expected to last 12 weeks".
Last week, protesters contacted Salford City Council claiming drilling would breach planning permission.
Energy company IGas has permission to start drilling to see what type of gas or oil can be found.
Mr Blaymires said: "We are looking for methane in the coal bed, but are then going into the limestone to look for shale gas."
He said had they wanted to carry out fracking, they would have sought the relevant planning permission.
Friends of the Earth claimed no environmental impact assessment (EIA) has taken place at the site and permission did not allow for shale gas exploration.
Residents 'support protest'
IGas said the development did not currently require an EIA.
Protesters from Frack Free Greater Manchester are living in tents at the site and say residents support them.
Earlier this year, IGas said there could be up to 170 trillion cubic feet (4,810 cubic km) of gas in the areas it is licensed to explore, in northern England.
In their annual statement, IGas said: "Operations have commenced at our exploration site at Barton. This vertical exploration well is designed to evaluate the gas bearing potential of the formations by taking both core samples and wireline logs."
The company said full analysis of the geographical cores is likely to take "up to six months to complete".