In ESI Africa Issue 4-2014 Jeanie le Roux, Director of Operations at Treasure Karoo Action Group, was invited to share an Opinion Piece on shale gas (pages 50 & 51). In response to Ms Le Roux’s arguments, Prof Philip Lloyd of the Energy Institute at Cape Peninsula University of Technology says that there is ‘nothing to fear’.
The world was taken aback when oil prices fell dramatically early this year. We had grown used to oil at over US$100/barrel. To drop to about half was unprecedented. Many in the oil production business are desperately revising their budgets; the rest of us are starting to enjoy an improved cash flow. Of course, what happened was that the United States had started to produce oil and gas at an unforeseen rate.
Prof Philip Lloyd's response originally appeared in Issue 1/2015 of our print magazine. The digital version of the full magazine can be read online or downloaded free of charge.
Today it is producing nearly 10 million barrels of oil a day and Saudi Arabia is increasing its output in an attempt to put the US producers out of business and so drive a price increase. Today the US is producing nearly 70 billion cubic feet of natural gas, 40% more than it was a decade ago. Believers in peak oil/peak gas have turned far quieter.
The change is the result of a huge technological shift. It has been found that the coal-black shales which underlie much of North America can be persuaded to yield oil and gas in economic quantities. All that it takes is a long hole more or less horizontally through the shale, and a bit of pressure to hydraulically lift the strata above the hole. Imagine a flat book with a balloon between two pages. Blow up the balloon, and the pages will be forced apart. In the shale, the fractures stretching out from the hole provide the oil or gas with a short path to freedom, and it can flow at a far higher rate than it can from the unbroken rock.
The shale is deep – typically about 2km deep – so it takes a high pressure to lift the rock. There is a fear that the high pressure will cause the hole to leak – but if it leaks, then you can’t create a high pressure! So the people trying to fracture the rock go to great lengths to make certain that the hole doesn’t leak – the fears of leakage are largely unfounded. We know this because over one million holes have been stimulated hydraulically during the past 20 years, and there has been precisely one documented leak – when there was an uncharted hole close to the one which the drillers were trying to pressurise. The damage the spill caused was minimal, for the simple reason that the drillers stopped pumping the moment they realised they were wasting their time.
The drillers have found that it helps to add a bit of sand to the water used to fracture the rock. The sand particles get carried into the fractures, and hold them open when the pressure is released. In order to make sure the sand gets carried along, the water usually contains a thickening agent rather like a gel, and a couple of other chemicals to make certain there is no corrosion of the pipes and similar effects. The total additives are less than 1%, but that is sufficient to make the water undrinkable. So the water coming out of the hole when the pressure is released has to be treated to remove the additives. It can be restored to full drinkability, but often it is only taken as far as being suitable for agriculture, for which there is usually a demand close at hand.
There is a fear that the additives could be toxic – and indeed, they often are, but it depends on what you mean when you say ‘toxic’. For instance, the acidity of the water is often adjusted with a dash of hydrochloric acid. Neat hydrochloric acid is indeed nasty stuff; but our stomachs are full of dilute hydrochloric, so once diluted it is essentially harmless. There is an idea that the drillers add benzene, which is indeed toxic. However, there is no evidence that drillers have actually used benzene as an additive, and it is a mystery why they would ever want to. It does not dissolve in water, and is flammable, so it could not do anything to improve the process. The fear of toxic chemicals has largely gone away since the drillers agreed to tell the world precisely what they add.
There is also a fear of gas getting into the water. Famously, the activist documentary Gaslands showed water coming out of a tap burning. However, that particular phenomenon was first observed in the 1930s, and a government enquiry in the 1950s had shown that the water was coming from a peat layer quite close to surface. It had nothing whatever to do with hydraulic fracturing of shale. And the other side of the story is that people have been drinking that water for around 80 years, proving that a dash of methane in your drink is not the end of the world! ESI
This article originally appeared in Issue 1/2015 of our print magazine. The digital version of the full magazine can be read online or downloaded free of charge.
Philip Lloyd is professor at CPUT’s Energy Institute, with prior experience in the mining and construction industries.