Shell promises ethical fracking
2012-09-10 09:26
Cape Town - Shell insists that it will conduct exploration for shale gas in the Karoo in an ethical manner after the government recently lifted the moratorium on fracking.
"Don't forget that we are not a fly-by-night. We have been in this country for 110 years as a company so we have a reputation that we have to protect here which obviously we don't want to damage," Jan Willem Egginck, Upstream (Exploration) Shell South Africa told News24.
While there are risks related to pollution of water from the practice, Egginck said that one of the most important aspects was to ensure well integrity.
It is critical that the well is sealed as the drill descends through to deeper layers of rock. Some operators do not effectively carry out this aspect of the procedure and the result is that gas migrates up and into water reservoirs.
"Natural gas wants to migrate up," said Penn State University geologist Dave Yoxtheimer, who works at the Marcellus Centre for Outreach and Research
Contamination
"It's lighter, it's less dense. And it finds itself getting trapped in these shallower, more porous formations. And during the drilling process you can go down through these shallower formations. As you're drilling through, suddenly you've created a conduit for those gasses to escape."
The movie Gasland demonstrated the effect of methane contamination of water, but Egginck argued that unscrupulous operators did not always check their well integrity to prevent gas leaks and pollution.
"The other risk is what is the risk of gas landing up in the water like they pretended in the Gasland video. These problems we've seen in the [United] States are all related to well integrity problems. You haven't drilled and sealed off your well properly in the process," he said.
As the well depth increases, operators should ensure that it is able to withstand the same pressure that will be applied during the fracking process.
The sealing of the well is usually done with cement and in stages to produce a tight seal. Every section is pressure tested to make sure that it will withstand operational pressures.
"You have to pressure it to such an extent that it's the pressure that is similar to the one you use in fracking, obviously not a lower pressure. If you see a leak, you have to repair it or re-drill the hole; you should not proceed.
"The leaks you're seeing in the States may be related to these well integrity problems of these operators not diligently doing their work," said Egginck.
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