This is according to Prof Gerrit van Tonder of the University of the Free State’s Institute for Groundwater Studies, who spoke at the Geological Society of SA’s Groundwater Division conference in Durban recently. “Shale gas can be a game changer for energy supply. Although it could power the world, it may have a devastating effect on the environment. Somewhere in the middle lies the solution,” said Van Tonder.
The underground structure of the Karoo basin is such that any pollutant will always migrate to the surface. If pollutants from the fracking process are leaked through failures in gas drilling wells, an area of up to 300ha downstream from the leak could be contaminated over a 30-year period. Should a gas well fail along a natural fault line in the rock, pollutants could contaminate boreholes within days.
Citing figures from Dr Tony Ingraffea from Cornell University in the USA, Van Tonder said that all fracking wells were shown to fail over time, leading to methane contamination. “Within the first year, 6,2% of wells will fail. Over 20 years, 60% fail and they all fail over time. The industry has not fixed this systemic problem because it can’t,” Van Tonder said. The total impact that fracking could have on Karoo groundwater depended on the area involved. “Risks depend on scale. If we frack only 0,5% of the area (the area for which Shell has a gas exploration licence), I’d say go for it. But if they want to frack 30%, I’d say no way.”
Flow-back of fracking fluid posed one of the greatest environmental concerns. Van Tonder said government should introduce regulations to force companies to disclose fracking fluid content. Kevin Pietersen, SLR consulting director, said it was important to tap into unconventional gas resources, as SA citizens needed clean, affordable energy. “However, key to this is preparing a commercial and legislative framework that’s attractive to investors, while ensuring a safe and environmentally-accountable regime.”
Surina Esterhuyse of the University of the Free State’s Centre for Environmental Management said policies should be developed in a phased approach in conjunction with mining, while SRK consulting principal geochemist Richard O’Brien said baseline monitoring was needed to determine ambient conditions and chemical composition of drilling zones before fracking started.
Water Research Commission CEO Dhesigen Naidoo said: “We need scientific information to make the right decision. We can then harvest (the gas) in a way that could set the benchmark for international best practice, or do it badly and regret it for a long time.” Pietersen said if shale gas were discovered in economic volumes it would take at least 10 years before commercial fracking could begin.