6th May 2014

The organisation responsible for ensuring the safety of Britain’s oil and gas wells has revealed there are no regulations covering a key part of the drilling operation.

The information emerged in a response by the Health and Safety Executive (HSE) to a request by Balcombe villager, Sue Taylor. She submitted 20 questions under the Freedom of Information Act on the distance between onshore wells.

In responding to her FOI request, the HSE revealed:

• There are no UK regulations on the distance between individual onshore oil and gas wells and it is up to the operator to decide how close they should be.
• There are no UK regulations on the number of vertical boreholes that can be drilled on one pad. Again it is up to the operator to decide.

Last week, Sue Taylor raised concerns about the distance between Cuadrilla’s exploratory oil well at Balcombe, and an older well drilled by Conoco in 1987. She told the planning committee considering Cuadrilla’s application to test its well that the two boreholes were only 10 metres apart. The integrity of the old well was not known, she said, and the risk of drilling nearby was unquantifiable.

In its response, the HSE said operators had policies and procedures for controlling the directions of their wells. But it revealed that Cuadrilla did not specify the minimum distance between the Conoco well (Balcombe-1) and its own vertical well (Balcombe-2) when it submitted designs before drilling in 2013.

The HSE also revealed that neither it nor Cuadrilla carried out any physical tests on whether there was a connection underground between the Balcombe-1 and Balcombe-2 wells.

The Balcombe-2 well had a horizontal extension, known as Balcombe-2z. When asked whether this horizontal well intersected with Balcombe-1, the HSE said no. But it said vertical boreholes were “seldom, if ever perfectly vertical”. Despite this, on pads with more than one well, the typical distance between the centre of each well is 4.5 metres. There were, according to the response, no records of instances where onshore wells had collided.

The HSE would not release reports produced at the time Balcombe-2 was drilled, either from its own staff or those by Cuadrilla. It would also not reveal the depth of each layer of casing on the well. The Freedom of Information Officer, Jennifer Donaldson, said this information was commercially-sensitive and likely to affect the level of investment in the industry.

“I have taken account of the genuine public concerns over the potential environmental risks from shale gas drilling”, she said. “But I believe it is in the wider public interest that operators are able to provide the level of detail HSE requires in their weekly drilling reports, to ensure that HSE can effectively regulate the risks to health and safety from their activities.”

Click here to see the full list of questions and the HSE response