|Fig. 1: Illustration of hydraulic fracturing of shale gas. (Source: Wikimedia Commons)|
Exploiting the natural oil and gas deposits of our planet allows us to fuel our cars, to heat our homes or to produce plastic. The enormous demand for oil and gas makes them to some of the most valuable trade goods on our planet. Thus, countries and companies always seek for new sources to produce oil and gas to have an influence on the market. Another important factor is that many deposits are in conflict areas and governments seek for ways to be less dependent on the supply from these countries. In 1947 first experiments with hydraulic fracturing were performed to find a way to extract oil and gas more efficiently. Already in 1950 it was commercially applied for the first time and today more than one million of oil and gas wells in the USA use this technique.  However, in many countries hydraulic fracturing is a controversial topic due to environmental dangers.
In 1947, Stanolind Oil performed hydraulic fracturing experiments in the Hugoton gas field that studied the effect of pressure on the efficiency of wells.  These tests were rather unsuccessful since they did not increase the production rate by a lot. However, in 1949 the Halliburton Oil Well Cementing Company received a patent for hydraulic fracturing and applied it commercially.  Over the time the techniques improved and today massive hydraulic fracturing is used to produce oil and gas where it was impossible before.
Using powerful pumps, fracturing fluid is inserted into a wellbore, the pressure increases underground and the rock cracks.  By adding proppants such as sand or ceramic to the water, one can ensure that fractures stay open. The efficiency can be improved by drilling horizontally into the rock, as shown in Figure 1. This allows to crack the rock in the area where the deposit is and reduces the number of wells that are needed, which makes the production more profitable. 
Unfortunately, this technique to produce oil and gas comes with a long list of risks for the environment. The cracks in the rock could allow chemicals to enter surface water or groundwater that might be used for drinking water production.  Also, greenhouse gases like methane can stream through the cracks of the rocks. [5,6] Moreover, the water that is pumped into the well comes back up the well to allow the pressure to release and this water is contaminated with chemicals and needs to be disposed properly.  Another risk is that the vibrations during drilling might cause small earthquakes. 
Every country must decide on its own, whether the potential environmental risks of hydraulic fracturing are worth the benefits or not. Increasing the gas and oil production and reaching deposits that were inaccessible before allows countries to be more independent from imports, however this comes with the great risk of irreversible damage for the environment.
© Constantin Dory. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
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