Hydraulic fracturing or geotechnical fracking is the exploitation of the pressure of a fluid, typically water, to create and then propagate a fracture in a layer of rock in the subsoil. Fracking is carried out after a drilling in a rock formation containing hydrocarbons ( oil or natural gas). The objective is to increase the permeability. Improving permeability improves the production of oil or gas contained in the subsoil and increases its recovery rate.
The first step in the extraction process is the digging of a vertical well on the surface with a depth that can reach three kilometers. Then, the perforation will continue, giving a turn of around 90 degrees. This horizontal extension of the well can range between one and two kilometers. In this way, the well reaches the L shape.
In this well of one of the tubes through which an explosive package that explodes transported in the lower part was introduced, create small fractures in the tubes, which put the inside of the well in contact with artificial substrate soil.
Then, millions of liters of water, sand and chemicals are injected at high pressure. This pressure causes the underground rock to release fossil fuels (natural gas or oil) trapped inside it. Due to this same pressure, the gas is covered to the surface, while the sand injected causes the fractures in the rock to remain open allowing the filtration of more gas.
Advantages and disadvantages of fracking
One of the great advantages of this technique is that it allows the exploitation of gas reserves that were previously considered unattainable. These sites provide great benefits to countries, local communities and industry. In addition, different countries help achieve greater energy independence with successive geostrategic benefits.
Fight against climate change
Initially, this technique received support from different sectors, including environmental groups. This was due to the fact that gas burning emits less CO2 than burning coal or oil. However, later research questioned the advantages of this technique in the fight against climate change. On the one hand, own natural gas (CH4) is a potent greenhouse gas, its direct filtration into the atmosphere being very dangerous during the extraction process.
On the other hand, the race for the exploitation of these sites may, according to experts' comments, stagnate in the development of truly clean renewable energy sources such as photovoltaic solar energy, wind energy, geothermal energy or hydraulic energy. In addition, other experts argue that, although the burning of gas is cleaner than the burning of traditional fossil fuels, the global increase in energy consumption would inevitably lead to climate change.
Impact on groundwater
One of the problems derived from fracking is the possible contamination of the wells and aquifers that provide drinking water to the population. The industry argues that the cement barriers introduced in the perforations prevent the possible passage of harmful substances to the layers of groundwater where potable water can be found.
However, several investigations by Duke University and the EPA have shown the presence of methane, chemical solvents and other substances in water samples taken near the boreholes.
Impact on surface waters
During the fracking process, a considerable part of the mixture of water, chemicals and sand that is injected into the drilling returns to the surface. In addition, in this process, water transports substances that were trapped in the depth to the surface.
This waste is highly polluting and can cause environmental disasters in case of leaks to rivers and surface water deposits. The classic example of this possible contamination occurred on the Dunkard Creek River in September 2009. An invasion of microscopic algae wiped out much of the river's indigenous life. Subsequently, it was learned that several companies had illegally discharged water from several drilling centers.
One of the proposed alternatives was to treat these waters in traditional treatment plants. However, several experts emphasized that these plants would not be prepared to purify these waters completely, especially with respect to the cleaning of radioactive substances (radio).
Last review: March 23, 2018Back