Safe shale: Lateral risks and the choice

  • Brine and new technology
  • Environmental management
  • British Society of Soil Science

By Bill Butterworth

5 December 2014


 Gas head

The building of a new gas connection on the mainland to link the gas grid to the Isle of White by drilling deep under the Solent was not just an un-heralded life-line to the people of the island.  It was a visible and verifiable test of the technology for drilling the top hole for shale gas exploration.  This was, and remains, a carefully monitored situation with ample evidence that it was environmentally safe, and no evidence that it was not.

While there is evidence that there is safe and tested technology for  drilling of the top hole for shale gas, it has to be admitted that the technology of managing the lateral drill-ways is more complex and is at the frontier of environmental management. The most commonly voiced risk here is in the production of millions of gallons of brine and how that is managed. Well, the county of Cheshire sits on top of enormous quantities of salt and the groundwater and the people on top are OK about it. In terms of shale gas exploration, there is new technology about; it is called electrodialysis. The process itself is not new but it has previously been economic only for very low concentrations of Sodium chloride (“brine” when in solution in water). However, researchers in MIT (Massachusetts Institute of Technology in the USA) working with the KSA (Kingdom of Saudi Arabia) have shown that a multi-stage process can be economic and allow the recycling of the water – so dramatically reducing water demand and the risks involved in what to do with the spent liquids.

There are other worries, of course. Nobody has all the answers till after the event. Monitoring what goes down the hole and what comes out, and what to do with it all, is critical. Firstly, there initially was much talk about earthquake risk; now largely discredited. Putting it simply, Blackpool has always had earthquakes. Millions, even trillions, of tonnes of earth’s crust is under tension and stress and, occasionally, it moves a bit. Now, if that tension and stress was on the edge of moving and causing a detectable quake, what fraking might do is trigger the quake which would have happened anyway. More than that, what the injection of fluids might do is lubricate the movement which was about to happen anyway and make a series of short movements which would reduce the effect of the quake. Blackpool might well have less detectable earthquakes, not more.

There is, in fact, an enormous amount of experience with deep drilling and putting the cuttings and spent fluids on the field close by – safely and under supervision by the Environment Agency.   The Agency people are well organised and always operate on the precautionary side. How might we add to that strength? Well, the most trusted soil scientists in the world are the Members of the British Society of Soil Science. They could add credible technical knowledge and independent professional judgement to monitoring.

Would all of these things solve and eliminate all the risks? No, the world is not like that. However, we do have to make a choice. There is a significant risk of a significant short-fall in power security and that might be very serious in consequences. It is a question of a balance of risks and sensible, common-sense, independent monitoring.