As oil reserves deplete, the most common Enhanced Oil Recovery method is a process called water flooding, which is a process through which water is pumped into the reservoir. Carbon dioxide (CO2) or nitrogen (N2) flooding is even more efficient.
The increased pressure displaces significantly more oil for extraction from the well, allowing recovery of around 20 to 40 percent of the reservoir total. However, this method also increases production costs, due to the work involved in sourcing and disposing of the water.
Carbon dioxide (CO2) or nitrogen (N2) flooding works along the same lines but is even more efficient. Here, water and CO2 or N2 are pumped into the reservoir alternately.
This yields significantly better results than water alone, allowing recovery of at least another 10 to 15 percent of the oil reserve. A further benefit is that the gas, injected under high pressure, is easy to separate from the recovered oil and can then be pumped back into the system.
Linde supports these EOR processes with air separators that produce the nitrogen required.
