Enhanced Oil & Gas Recovery
If natural gas and petroleum resources can no longer be exploited through natural reservoir pressure (primary production) or by introducing water (secondary production), so-called tertiary processes, known as Enhanced Oil Recovery (EOR) or Enhanced Gas Recovery (EGR), are used. Tertiary processes include the injection of gases into the reservoir. During "fracking" so-called "shale gas" is extracted. Here, aqueous suspensions are injected into rock layers at high pressure, breaking up gas-containing layers so that natural gas is released.
To further exploit natural gas or petroleum resources beyond primary or secondary processes, gases such as nitrogen or carbon dioxide are pumped into the wells at high pressure. With this method, the yield of a deposit can be increased from approx. 40 % to up to 60 %.