How Karoo tests will help in monitoring fracking
Several research projects are under way to probe the environmental effects of fracking shale gas in the Karoo — including one that would entail digging one of the deepest holes on Earth.
"We want to go deep into the abyss, to a depth of at least 10km," says senior Nelson Mandela University geologist professor Maarten de Witt.
The hole would be more than twice the depth of AngloGold Ashanti’s 4km-deep Mponeng gold mine (among the deepest mines in the world) but shallower than Russia’s 12km Kola Superdeep Borehole, the deepest hole in the world.
At a conference in Port Elizabeth recently, De Witt and other scientists provided a glimpse into some of the preliminary research work on the controversial plans to hydraulically fracture (frack) the central Karoo region.
De Witt indicated that the big hole would most likely be near Cradock in the Camdeboo valley. Likening the proposed research centre to a kind of African "Silicon Valley", he said the focus would be on developing skills and knowledge around deep-drilling, geology and methane measurement.
He declined to reveal clear timelines, or details of who might pay for such an ambitious venture, but said the design phase was expected to get under way before year-end.
Digging down to 10km could take four to five years, De Witt said, noting that the last drilling stage would be complicated by steadily rising temperatures closer to the Earth’s core.
De Witt also outlined details of other fracking-related research projects by students at Nelson Mandela University.
In one of them, students drive around the region in a bakkie equipped with methane-measuring devices. They record existing levels of methane gas from sewage water-treatment sites, natural hot springs, fertilised farm fields and abandoned wells dug by the Soekor exploration company.
If large volumes of methane leak from gas wells during future shale-gas operations, the fracking firms could easily claim the gas had been there all along — hence the need for baseline studies to record current levels.
The purity of underground water will also be tested — although it remains unclear how many of the 37,000 wells in the Eastern Cape will be tested prior to fracking.
Other experiments involve spraying fracking fluids onto indigenous vegetation to test the response to future pollution events. Although fracking relies mainly on high-pressure water to crack open underground shale rock, fracking fluids also contain grains of sand and a wide variety of potentially toxic chemicals.
Professor Michiel de Kock, a paleomagnetist from the University of Johannesburg, said a 2.3km-deep well was dug near Willowvale recently in a project funded by Shell. "Some of the deep water was better than the surface water," he said. The drilling revealed very little gas-rich shale rock.
The baseline water quality about 1km underground would be measured by two boreholes, while the third would be used to get a better understanding of geology at depths of up to 4km.
An average of two and a half earthquakes (above magnitude 3) were measured every day in Oklahoma — suggesting a seismicity rate about 600 times higher
Black said six stations would be established to measure microseismicity in the region – one of the major emerging concerns is the potential for fracking and other unconventional mining methods to trigger earthquakes, either from rock fractures or the disposal of wastewater in the fracking process.
Two years ago, the Oklahoma Geological Survey warned about the increasing risk of earthquakes due to the recent expansion of the oil and gas industry in Oklahoma.
Oklahoma state geologist Richard Andrews and state seismologist Austin Holland said that historically, there used to be about one and a half earthquakes every year (above magnitude 3) on the Richter scale. Now, an average of two and a half earthquakes (above magnitude 3) were measured every day in Oklahoma — suggesting a seismicity rate about 600 times higher.
Andrews and Holland said this increase in seismicity was "very unlikely" to be the result of a natural process, but "very likely" the result of injecting oil and gas wastewater into underground disposal wells. In SA, there is growing concern from environmental groups and scientific experts about the need to understand the state of the environment and crucial water resources before Shell and other exploration companies get the go-ahead to start digging production wells.
This was one of the main objectives of the recent meeting in Port Elizabeth, organised by the Academy of Science of SA (Assaf). In 2016, Assaf produced a lengthy expert report setting out 19 recommendations to the government to guide proposed exploration and production by the shale-gas industry. Some commentators have hailed gas fracking as a potential "game changer" for SA, citing estimated Karoo shale-gas resources of up to 400-trillion cubic feet (tcf), but Assaf believes the reserves are likely to be in the region of 20tcf.
Shell, one of five groups hoping to profit from gas discoveries in the Karoo, suggests there is only a 10% chance of finding commercially viable reservoirs. "There is a strong likelihood that this process may not proceed beyond exploration," Shell SA representative Nigel Rossouw told the conference.
Derek Light, an attorney representing 400 landowners in the three Cape provinces, said the message he was picking up from Shell was that the government should not "scare away" gas companies by creating too many regulations to control fracking. "But we must not forget that regulations are there to protect our environment. If this is ever to go ahead, it has to be properly regulated," he said.
His message was echoed by several other delegates, including Jan Glazewski, a professor of marine and environmental law at the University of Cape Town.
Noting SA’s poor record in regulating pollution from existing mines and abandoned mines, he said all three branches of government – local, provincial and national — should have adequate monitoring and enforcement capacity in place before any fracking began.
"They must have a clear mandate and teeth — including the power to arrest people," Glazewski urged.