Shale gas exploitation has recently been given the go-ahead in the UK. With all the excitement, claim and counter claim, it would be easy to forget that to date not a single molecule of methane from shale gas has been produced and sold. We have drilled one shale gas well. That’s an 8½ inch borehole in Lancashire, a little like pushing a pin through the ceiling of your living room and looking through the hole. It does not tell you much about what’s in there. So will this new source of gas make a difference?
Let’s start with some numbers. Present UK annual production of natural gas is around 1.5 TCF (trillion cubic feet), but each year we use about 3.3 TCF. In the USA in the last 10 years, approximately 20,000 shale gas wells have been drilled and they now have an annual shale gas production of 3-4 TCF per year. If we use the USA as an analogy, the UK would need to drill thousands of wells to prove the reserves exist and make up just a part of the annual 1.8 TCF short-fall. Unlike wind energy, where there has been a move to develop it offshore, this is ecomomically unviable for shale gas because the rate of flow of gas for each well (i.e. revenue) is low relative to gas from other types of rock . So we cannot get away from it – researching the risks and an open and honest debate about them is an essential element in gaining the social acceptance of the technology that will be required.
Durham University have been working on this. Firstly, despite what we are often told, to date in the USA there is not one proven case of contamination of drinking water due to fracking after hundreds of thousands of fracking operations. But the contamination question led us to establish a guideline for a safe vertical separation distance of 600m between the depth of the fracking and shallower water supplies. If adopted, contamination of water supplies would be extremely unlikely.
We’re working on other issues. For instance the water used for fracking flows back to the surface in a controlled way after the operation is over. This water is contaminated with naturally occurring radioactive material, otherwise known as NORM. Even with the hundreds to thousands of wells that would be required to make an impact in the UK, the amount of radionucleides such as radium 226, is going to be a fraction of that produced by the medical sector, universities and existing oil and gas production. It would need to be cleaned and any residue safely disposed of. The technology exists – so this is not a show-stopper.
USA shale gas production took off in the last 10 years because the country has thousands of onshore drilling rigs available to carry out the drilling and helpful landowners who in some cases own the gas under their land. Both are not the case in the UK. Even if the social acceptance is forthcoming, it will take years for the industry to gear-up to drill enough wells to make an impact on the production-consumption gap. The science behind extraction of the gas reserves may in the end be secondary to issues of public trust in oil and gas companies, regulators and local and national government. The gas is there, but companies in the UK need what was recently coined a “social licence to operate”. Without this the wells will not be drilled and shale gas will only ever make a tiny contribution to our economy and energy security.
Richard Davies is director of Durham Energy Institute, one of Durham University’s eight Research Institutes
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