It’s a story of Machiavellian political intrigue with oil companies, Scottish lochs, nuclear submarines and a government at war with the socialist industrial heartlands of its country. Chic Brodie, an SNP back bencher first broke the seemingly preposterous story that, in the mid 1980’s, the Tory government of Margret Thatcher intervened at the highest levels and stopped BP exploring for oil in the Clyde estuary for “national security” issues.
This tale of political intrigue is not just interesting from a historical perspective. If there really is oil in the Firth of Clyde, it could be added to the oil reserves of a newly independent Scotland. Most importantly it would bring a much needed boast to the once proud shipyards and docklands of the Clyde. It would spread the wealth of our oil boom from the Granite City in the east to the industrial heartlands of Glasgow. So is there any truth behind the story and can we separate the facts from the fiction?
First let us look at what we know of the geology. For this we have managed to find some of the original data collected in the early 80s which was previously considered as lost. Since there are no boreholes sampling the rocks below the seabed we must rely on looking at the geology around the Firth of Clyde to predict what is beneath it. There is plenty of great rocks for geologists to get excited about on both the mainland and the islands.
To produce an oil reservoir we need three things. The first of these is an organic rich “source rock”, to generate the oil and gas. The Carboniferous aged coal deposits of the Midland Valley satisfy this requirement very nicely, under the correct conditions they are known to produce significant volumes of gas and even some oil.
The second requirement is a reservoir rock, a porous layer that can hold the oil and gas like a sponge holds water. The clue to this comes from the red and blonde sandstone tenements of Glasgow which are built out of such sandstones. These were lain down by rivers in the coal measures and later in the sand dunes of a vast desert that covered much of northern Europe and beyond. These rocks occur around the Firth of Clyde from the city of Glasgow to the Isle of Arran and have fantastic reservoir potential.
The final ingredient is a structure – a giant container to trap the hydrocarbon in. Studies of old seismic data, shot in the early 80’s shows several large structures which appear to have excellent trapping potential at the right levels.
So we have all the elements in place, in fact, the same combination of factors has been associated with numerous oil and gas discoveries in the East Irish Sea to the south, including the 220 million barrel Douglas Field off the North Wales coast or the Morecambe Bay field off Lancashire . From this we can say that there is certainly potential for oil and gas in the Clyde.
And that is certainly what BP thought in the early 1980s when, in conjunction with Glasgow based Britoil who they later took over, they collected two large seismic surveys, a regional one in 1981 and a more detailed one over a specific prospect in 1984. Seismic surveys are like giving the Earth a giant ultrasound and reveal the internal structure of the crust. In the same year BP and Britoil applied for, and were award, Licence number PL262 which covers 140 square kilometres just west of the tiny island of Ailsa Craig. A licence gives the holder exclusive rights to explore in an area for a certain period and BP held this licence for four years from 6th April 1984 until April 1988. During that time they collected the seismic data and analysed the results. We obtained some of that data, although it was previously thought to have been lost. We can confirm that there is a large structure there that would be a good target for exploration. Despite this when the licence period came to an end BP and Britoil relinquished the licence. No wells were ever drilled in the region and it is possible that the prospect was considered to be too high risk or too small to warrant a well, especially since gas is more likely than oil.
Recently de-classified documents suggest that BP’s reasons for giving up on the area were not necessarily related to the geological risks of the project. The MOD who had two submarine bases in the region, Faslane and the American Holy Loch, were not keen to allow other activates in the region that might interfere with their clandestine activities. The prospect sits directly below the deepest part of the main navigation channel between Arran and the mainland. Chic Brodie’s investigation in 2013 revealed numerous documents illustrating how the MOD had secured a blanket ban on drilling in the Firth. In June 2014, Michael Heseltine, Margret Thatcher’s defence minister at the time openly admitted that they had blocked oil exploration in the area. In fact he was proud of the fact that they had sacrificed jobs on the Clyde and a potential west coast oil boom for a seat at the nuclear table.
What is less clear is whether there is actually any oil or gas out there and if so how much. There is plenty of circumstantial evidence to suggest that BP’s exploration results were looking promising. George Younger, the then Scottish Secretary of State, in a letter to The Times newspaper in 1983, stated, “The oil companies are playing their cards pretty close to their chests, but they are expecting something exploitable (in the Firth of Clyde area)”. Ian Clark, a Britoil senior executive at the time reported encouraging results in 1984 but then went very quiet on the topic.
The truth is that without drilling it is impossible to say whether oil or gas is present in the region or not. There are many places in the World were favourable conditions exist but hydrocarbons are not found. What we do know is that the only way we will ever find out is by lifting the exploration ban and then drilling wells to test the subsurface. We also know that this will only happen in an independent Scotland, unshackled from Trident and secret submarine bases. Only then will we ever know whether Glasgow will get the oil boom that it was due over 30 years ago, a boom that could have stopped the Tory destruction of the ship building industry and prevented years of poverty and deprivation in one of our great Victorian cities.
John Howell is a professor of Petroleum Geology at the University of Aberdeen.