It was unlikely that hydraulic fracturing, or fracking, deep underground in the Karoo would contaminate ground water, MPs were told yesterday.
At a briefing of a joint meeting of the mineral resources and energy portfolio committees on the potential for shale rock gas extraction, Petroleum Agency of SA (Pasa) frontier geology manager Jennifer Marot said: “I believe… that it is unlikely that ground water would be contaminated by the fracturing process.”
Fracking involves the injection of millions of litres of water, sand and chemicals at high pressure to release gas in a well.
Pointing out that extracting gas from a rock layer as far as 2km underground would require a horizontal shaft extending possibly another 1.8km, she said that high standards needed to be applied to the cement casing – or protective well casing – of the shafts.
If the casing was not done correctly, the gas might infect the aquifers of water-bearing permeable rock.
She acknowledged too that the immense use of water in the process would be a major challenge in the water-stressed Karoo while the process of exploration could require “many wells” to be drilled.
Noting that Pasa was involved in high-level discussions with US counterparts, she said one well drilled in the Marcellus shale used 380 000 litres to drill and another 21 million litres to frack the well. This was the equivalent of eight and a half Olympic-sized swimming pools and one month’s water use for a golf course. She suggested that salty water from deep aquifers “or even acid mine drainage” might also be usable in the fracking process.
One option was to insist on “a single pad” – to cut back on a plethora of wells being dug from which to carry out exploration – and making it subject to a rigorous environmental impact assessment.
“Until we know how large the resource is, we cannot predict what the development profile would look like.”
Flanked by Pasa chief executive Mthozami Xiphu, Marot said that gas resources in the karoo could be as little as 140 billion cubic metres – itself five times the size of the existing Mossgas – or anything up to 2 trillion cubic metres. “Most conventional wells can produce gas for 20 to 30 years,” she said.
“There is potential for this resource to be huge. We say that because the main point that we need to make… without exploration it is impossible to evaluate the resource.”
Noting that the agency – which promotes the exploration of oil and gas – had the mandate to evaluate the extent and value of the resource, Marot said: “We need to look at that resource and the effects it may have on South Africa’s energy mix.”
Noting that “ecologically responsible” fracking was expensive, particularly regarding water usage and disposal, she said the gas industry in South Africa was “in its infancy” and the infrastructure was undeveloped, including pipelines, service providers and laboratories.
However, the industry might provide South Africa with “much-needed, cleaner energy”.
The agency had the mandate “to promote and regulate ecologically sustainable hydrocarbon for the benefit of all South Africans”.
Xiphu noted that in terms of the law PetroSA – the state oil and gas company – would hold a 10 percent share in gas exploration while a further 10 percent would be awarded to empowerment partners of any company that was given the right to exploit the gas.
Anglo American, Shell International, Sasol – with Norway’s Statoil and Chesapeake of the US – have applied to explore for shale gas in the Karoo. - Donwald Pressly
No comments:
Post a Comment