ENERGY giant Perenco is currently carrying out a large geological survey in the area of its Wytch Farm site to assess the possibility of future oil reserves.

Dorset Council has issued an order restricting public access to a number of roads to enable the company to carry out its work.

However, green campaigners say money should not be invested in further fossil fuel extraction in such an environmentally-sensitive area such as the Jurassic Coast.

Perenco (UK) Ltd, which bought all stakes in the oilfields from BP in May 2011, was given permission by Dorset County Council to extend oil production at the site for 21 years in 2013.

Currently Wytch Farm, the largest onshore oil field in western Europe, produces 20,000 barrels per day and remaining reserves are estimated to be 40m barrels.

A Perenco company spokesman confirmed: "Perenco is undertaking a 3D seismic programme in the area of Wytch Farm, Dorset.

"This is designed to gather new data relating to the subsurface structures in the area.

"It is a safe, low impact, highly regulated and widely used activity in the oil and gas industry.

"It has no negative impact on wildlife or the environment. The 3D campaign commenced in mid-August and will last no longer than 70 days."

The local authority said the approval was in line with Government policy.

Green Party councillor Kelvin Clayton said his group on the council stood together in opposition to the work.

"We would be totally opposed to any work like this whatsoever," said Cllr Clayton.

"All carbon-based fuel sources need to be kept underground. It is as simple as that.

"A solution would be to build the Navitus Bay wind farm.

"I do not care what the Government policy is, this should not be happening."

Environmentalist Angela Pooley, of the East Dorset Friends of the Earth Group said: "We should not be investing in further fossil fuel extraction, especially in areas as sensitive as the Purbeck coast.

"A wind farm was turned down because of the potential impact on the Jurassic Coast, yet here they are doing further work with the possibility of oil extraction."

The geophysical survey is being carried on behalf of Perneco by the company Geofizyka Torun.

Perenco say they have an obligation under their Oil and Gas Authority Licence to carry out a 3D survey in order to further map the deep geology of the area.

An information leaflet released by Perenco said: "The survey is being undertaken to piece together as detailed a picture as possible of the geological structure of the Wytch Farm Oilfield."

Specialist vehicles including 'vibrator trucks' will be driven over the survey route. At various points a large pad underneath the trucks will descend and vibrate the ground.

Other methods being used include sensitive seismic sensors being planted on the ground surface and test holes being drilled from a small tractor-mounted drill.

Temporary positioned nodes may also be seen near roads and tracks while the survey takes place.

The road restriction order, issued by Dorset Council, stated: "The order will enable Perenco safe access to carry out geological surveys of the sub surface of various sites throughout Purbeck to assess the possibility of future commercial oil reserves."

"Please note the closures will be in operation, as and when indicated by signs on site.

"The dates stated could slip if we experience adverse weather.

"Advanced warning signs will be placed on the road in advance of the closure to indicate the exact dates the closure will affect the road.

"All works carried out in the summer holidays will be carried out overnight."

A DORSET Council spokesman said: "Government policy is to continue to support the exploration and production of hydrocarbons through the award of licenses for exploration and production.

"These resources are considered to be required to support the transition to other forms of energy generation and this council’s planning policies support exploration for oil and gas.

"While an increase in low carbon sources of energy is vital to meet targets to reduce carbon emissions and to mitigate against climate change, there continues to be a need for oil and gas, with the Government’s energy policy being to ensure secure, diverse and sustainable supplies.

"The seismic testing proposed by Perenco is ‘permitted development’ by virtue of the Town & Country Planning (Permitted Development Order) 2015. Planning officers have reviewed the seismic scheme proposed by Perenco and consider it meets all the criteria required to be classed as permitted development.

"We have liaised with Perenco over a number of months to ensure that any potential impacts are minimised, particularly on wildlife.

"We are satisfied that the work will be very short term in any particular location and have little or no adverse impacts."