Gas reinjection in the pre-salt: how does it work?

Natural gas reinjection is a widely used technique to increase oil production, which basically consists of the process of reinjecting natural gas into the reservoir after production. In Brazil, with the development of pre-salt, reinjection has been growing since 2013. This is because in reservoirs where there is the presence of natural gas and oil, which predominate in the pre-salt layer, it is common for natural gas to be extracted and reinjected to maintain pressure in the well, allowing to produce more oil.

Studies released by the ANP (National Agency of Oil and Natural Gas) and the EPE (Energy Research Company) estimate that this technique can increase by 25-30% the recoverable volume of oil in the field, when compared to water injection, another reinjection technique in oil production. Often, too, the field is only economically viable if the practice of natural gas reinjection is used.

Another issue is the quality of natural gas in the pre-salt. Often, the producer is obliged to reinject part of the natural gas produced, because of a high CO2 content that makes it impossible to move through pipelines. In addition to optimizing oil production, reinjection also prevents gas burning, preventing impacts on the environment.


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