DEAD COW: what is fracking?

The decision of the oil company Shell to temporarily suspend, during the last weekend, its operations in Dead cow as a result of the seismic activity He again put on the mat the environmental drama that crosses that area of ​​Patagonia due to the extraction of unconventional hydrocarbons.

Although the company in question resumed drilling as of Monday, the truth is that the paralysis came as a consequence of an almost unprecedented succession of tremors in the Neuquén basin. According to scientific surveys to which he agreed iProfessional only in the last week 20 earthquakes happened in that area of ​​the country and everything points to the return of “fracking” around the town of Añelo.

The technique in question involves drilling wells by breaking underground rocks with explosives. And the subsequent injection of a mixture of water – a resource by which the oil companies pay just 4.90 pesos per cubic meter – and a battery of formulations that can range from 20 to 500 additives.

Fracking -or hydraulic fracturing- combines aspects of consolidated oil exploitation and the most questioned mining work. Currently facing opposition from environmental organizations, local and international NGOs, and even residents of the Vaca Muerta area, from these same tremors that now repeat.

At par, exploitation by “fracking” has been generating an annual volume of “flowback”, that is, water with chemicals and other industrial waste returned by each drilling, equivalent to just over 500 50 meter long Olympic pools.

The “flowback” culminates housed in 60 sinkholes that house the same liquids without any treatment, in permanent filtration towards the Huincul ridge, the predominant geological fault in that area of ​​the Neuquén province.

The earthquakes in Vaca Muerta began to become regular from 2015, coinciding with the takeoff of the exploitation of unconventional in the area. Until then, according to works prepared by Javier Grosso, teacher and researcher at the Geography Department of the Universidad Nacional del Comahue, no tremor had been detected in the span of almost a century.

The collapse of the current international price of hydrocarbons, and the imposition of a quarantine that banished fuel consumption, gradually resulted in the deactivation of hydraulic fracturing equipment mounted in the Neuquén basin by oil companies like the same Shell, Tecpetrol -owned by the Techint group-, Wintershall or the French Total.

The depth at which earthquakes occur in Vaca Muerta coincides with the drilling ranges of the wells.

The tremors returned with the “fracking”

The easing of activities in the oil territories ruled by the Government as of May caused the return of activities in the reservoir. And, with it, a succession without pause of telluric movements that they are dangerous even to the same companies accused of provoking them.

“Observing the seismic activity that was registered in the Neuquén region in recent days, on both the Argentine and Chilean sides, we decided to preventively suspend the activities in Bajada de Añelo and we contacted the authorities of the province to tell them of the decision made “, Shell reported over the weekend more recent.

The thing not clarified by the company: if these movements occurred alongside the “fracking” that the oil company activated after the official green light to return to intensive exploitation in the South. And if the earthquakes in question were even felt on the same platforms of the company. The rush to stop everything could answer the latter.

Asked about Shell’s reaction to the tremors, Martín Álvarez Mullally, a researcher at the Petrolero Sur Observatory, told iProfessional: “It is very important that for the first time a company recognizes that it stopped activity due to seismic movements. Contrary to what Shell says, that the tremors occur due to aftershocks in Chile, we believe that it is due to the reactivation of the Huincul Ridge fault system as it has been happening since Vaca Muerta began to exploit. ”

“We understand that the induction of movements can occur due to two factors: the ‘fracking’ when it is done and the sinkholes, which is where large amounts of liquid waste are deposited, “he added.

The most recent warning of the tremor was known last Saturday, when a statement from the Interdisciplinary Group for Environmental Studies – made up of technicians and scientists from the universities of Comahue and Southern Patagonia, in addition to CONICET – approached iProfessional He detailed the “occurrence of a new earthquake in the Saturday morning 6 June, near Añelo “, known among oil tankers as the” capital “of Vaca Muerta.

“It is the second in the week with intensity greater than 4 degrees on the Richter scale. Over a total of 20 (earthquakes) registered in 6 days“highlighted the message.

Fracking includes the drilling of wells by breaking underground rocks with explosives and a subsequent injection of water and chemicals.

Earthquakes coincide with the depth of the wells

Days later, the organization exposed another aspect inherent in the same “fracking”: the tremors that have been registered in the Neuquén basin occur at a depth not exceeding 6 kilometers -coincident with the drilling ranges of the wells-, while the provinces with tradition in terms of telluric movements show activity to much larger underground brands.

“Strangely, for a province -by Neuquén- that has 600 kilometers of mountain range -more contact with the Andes than Mendoza or San Juan although with another seismicity-, not a single tremor has been registered in the vicinity of the cordillerana and precordillerana zone, even with two active volcanic systems such as Domuyo and Copahue“, they always indicated from the Interdisciplinary Group of Environmental Studies.

“For the province of Mendoza, the National Institute of Seismic Prevention (INPRES) recorded 14 earthquakes during these first days of June. Only 2 of them had the focus less than 9 kilometers, the rest exceeded 120 depth on average. Neuquén tremors are a few kilometers from horizontal perforations, between 5 and 6 deep. The Vaca Muerta earthquakes are the most superficial in the country, and the depth of its foci coincides with the horizontal branches of the fractures that began in January of this year, “he added.

Interviewed by iProfessional, Javier Grosso remarked that the brake imposed on hydrocarbon activity after the landing of Covid-19 practically completely finished with the movements in the basin.

“The area shook again from June 1. The decision to establish a Creole barrel price again encouraged work in the area. Now the earthquakes are being felt north of Añelo because it is the area where fracking began in December of last year, “he said.

“What happened in the last days is unpublished. There is no history in INPRES of successive earthquakes in the same week. And this occurs and it is verified that the area is measured with just 2 seismographs when the ideal would be to have 8 teams doing the work, “said Grosso.

To conclude later: “The succession of earthquakes is such that, even if all fracking were stopped again today, as a residual matter, tremors would continue to be registered many days later. The current scenario is of an intensity that is impossible to guess what can happen in Vaca Muerta in terms of environmental damage. “

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