Fred Starr recollects: Black arts at Wytch Farm

Materials World magazine
,
1 Feb 2015

Mentioned in December 2014 Materials World, Wytch Farm, in Dorset (pictured left), said to be Europe’s biggest onshore oil field and cited as a good advert for the black art of fracking, is a somewhat myth-laden tale. A sidekick from my days at the EU’s Institute for Energy, a chemical engineer from Romania, might have disputed the claims about the significance of the field. His family knew, from personal experience, how vital his country’s wartime contribution of 25 million tonnes of oil to Germany had been. Accordingly, the Ploesti refineries in Romania (pictured above) were repeatedly attacked by the US Air Force. Ever since, my colleague’s aunt has been somewhat deaf. Bombs, if they don’t kill, can perforate the ear drum.

Some would argue we are not comparing like with like. The Romanian oil fields were festooned with wooden oil rigs, each of modest output. In the 1970s, when British Gas began to explore the area around Poole Harbour (which includes Wytch Farm), it was then a nationalised industry, answerable to the people. Environmental impact had to be minimised, given that the shores of the Harbour are covered with yachting marinas. Brownsea Island, which sits in the Harbour, was one of the last enclaves of the red squirrel. It was hardly feasible for British Gas to build a forest of oil derricks on land or out in the bay. Directional drilling of multiple wells from one site was the answer. I kept in touch with what was happening, as we might have been needed on the corrosion front.

Another myth, that Wytch Farm was a BP initiative, is punctured. In fact, after its exploration phase ended, British Gas formed a partnership with BP. The latter was pessimistic, but oil was found in a sandstone strata about 800 metres down. BP considered this to be sufficient, but British Gas thought there were better prospects even deeper. 

So it was, and the Sherwood sandstone formation turned out to be a real bonanza.
It was doubles all round! Onshore oil is cheap to produce and, because the chances of finding any were small, there was no petroleum revenue tax. But, moving on to the early eighties, a newly elected Government artfully decreed that, as this was not a gas well, it was not the business of British Gas to dabble in such matters, insisting on the assets being handed over to the BP. That is how the BP story grew.

To those in British Gas who knew what had gone on, it was a dispiriting affair. Orders came down that we were to leave the site in top-notch condition but, as reporters used to say when invited into a den of iniquity, ‘I made my excuses and left’. Mine was that I was really a high-temperature corrosion man. Besides, what was the personal advancement in taking on a job like that? I wouldn’t be doing it for British Gas. If things worked out for BP, who would remember me?

Finally, how about the half truths regarding fracking at Wytch Farm? Yes, fracking does go on, but the oil is drawn from a permeable sandstone, not shale. If there is enough gas or water drive in the formation, the oil will find its way into the drill pipe. But the horizontal distances for drilling into the long elongated block of Sherwood sandstone are around 10km, so it is worth cracking open the rock to speed up the rate of withdrawal.

A good analogy for shale is that of a book that has been dropped into a bath and got thoroughly soaked. There is no way of drying it out, except by opening it page by page – a tedious process. So it is with shale. Fracking shale layers does not open much of the rock away from the drill pipe. Since shale is essentially impermeable, it means, even with directional drilling, having to drill from a large number of separate wells to get access to the gas or oil.
Where there are similarities with Wytch Farm is that the gas and oil have to be brought to a large, centralised complex to separate the gas, oil, sand and water. There has to be disruption of the countryside through the laying of temporary pipes from each of the many shale well sites. As British Gas found at Wytch Farm, camouflaging rigs and pipework is expensive.

We don’t form myths any more – we have the black heart of propaganda, especially in the energy sector, where we are continually confronted with so-called answers to the energy crisis. Most overlook what is asked of materials engineers. Sometimes we have ready-made solutions. More often than not, years of development will be needed – a joyful prospect to those squirreling away in R&D!