The drilling trucks have already started to arrive in Balcombe.
They head cautiously along a narrow track through Sussex woodland towards an old, disused oil well.
Documents filed with West Sussex County Council – and served to local residents – suggest unconventional oil and gas explorer Cuadrilla is set to start work near Balcombe, West Sussex this weekend.
So what are they up to?
Any activity by a firm known primarily for its interest in fracking is bound to be controversial, especially in a region where ‘community benefits’ are unlikely to swing the local town hall – but Cuadrilla insists they haven’t come here to do anything unconventional.
Indeed, at this point it would be illegal for them to frack. They have neither asked for, nor received, permission to do so. Nor are they primarily interested in gas.
But it wasn’t always that way.
The firm actually arrived in Balcombe in April 2010 – or at least their request for planning permission did.
The company wanted to drill in an old well, last used by US oil giant Conoco Phillips in 1986 to look (unsuccessfully) for oil.
The well has since been since plugged, abandoned and used as a storage site for the nearby woodland.
Cuadrilla applied to upgrade the platform and drill an exploratory borehole to look for hydrocarbons – oil or gas – at the site.
But technology and economics have changed and the Cuadrilla application went beyond what Conoco had done.
Appendix C of the 2010 planning permission suggested "There may be a need to stimulate the gas... stimulation is carried out by water under pressure into natural fractures in the shale formations... in some cases silicone sand is then pumped in.”
Appendix B – the seismic interpretation – also referred to horizontal drilling in order to access the previously unexamined shales. That would mean drilling sideways to follow the shale formation, potentially for kilometres.
In short the planning permission included provisions for what we all now know of as fracking - though it did depend how much oil or gas comes out through conventional methods.
Indeed when the issue resurfaced last year Balcombe Parish issued a statement on fracking saying the original planning permission “would permit the use of this technique”.
Oil or gas?
The planning document is also vague as to what, exactly, they were looking for. It reads; “the main aim of the exploratory well is to test for natural gas/oil trapped in the shale and thin sandstone layers."
This isn’t deliberate misinformation, not knowing which ‘hydrocarbon’ you are going to get out is quite common in the oil and gas industry. Gas and oil tend to coexist together. Most firms would want oil – it’s more valuable – but that doesn’t mean that’s what they will get.
Balcombe sits within the Weald Basin. According to a document prepared by the British Geological Survey (BGS) for the Department of Energy and Climate Change that area has seen multiple oil and gas wells drilled in the past and could be home to both shale gas and – potentially – shale oil formations.
The old Conoco well leads many to suppose its oil they will find - indeed that is what Cuadrilla themselves believe - but as recently as May the firm were still hedging their bets,“If Cuadrilla finds oil or gas” a statement read “a series of extensive technical, environmental and public consultations would take place before any further decisions are made.”
They are looking for oil – but the nature of exploration is that you can’t be totally sure what you will find especially in a region recently opened up for shale prospecting.
Shortly after that application, the first controversy around fracking started with reports of tremors linked to exploratory wells by Cuadrilla in Lancashire.
In December 2011 the firm issued a statement that “there are no plans, or regulatory approval” for hydraulic fracturing “at this stage”.
In fact, as local opposition mounted, the firm did nothing at all. But their planning permit only lasts three years and was due to expire this September.
An exploration company needs to find oil or gas to attract investors. Despite the opposition Cuadrilla has decided to go ahead in the last months of it’s time window.
So what will they do?
In short they will drill a well through various layers of rock, taking samples and testing for the flow and permeability of any oil or gas reserves they find.
They have applied for and secured a permit from the Environment Agency (EA) to handle waste – including, for example, gas released during the drilling which the company plans to flare.
They have also applied for a permit to handle Naturally Occurring Radioactive Materials (NORM) found in rocks deep underground.
The firm intends to carry out what is called an ‘acid wash’ at the base of the well. This involves using dilute acid to ‘clean’ the rocks, allowing any gas or – hopefully for the explorers - oil to flow up the well bore.
But it will also return water to the surface containing radioactive materials from the rocks which needs to be disposed of safely (see our Q&A on NORM).
And that – for now - will be that.
If they find nothing or just a small conventional oil well that Conoco somehow missed – the shale gas party will move to another town.
But if they find oil or gas trapped in shales under the Sussex hills, resources which can only be extracted by hydraulic fracturing then this is likely to be only the prelude to a far longer story.