Energy Recovery During Waterflooding Will Reduce the Cost of Oil Production
Perm Polytechnic scientists have developed a technology to increase the efficiency of oil production. To do this, during reservoir flooding, the energy already expended during production is reused. The Devon News Agency learned about this from a message from the Perm National Research Polytechnic University.
Waterflooding is the injection of water into an oil-bearing formation. This allows you to maintain in-situ pressure. Thus, oil is pushed to the bottom of the well. The system operates due to high pressure in the piping system.
For the first time, PNRPU scientists proposed reusing this energy reserve using the recovery method (returning energy for its reuse). In this case, the existing well infrastructure is used. This does not require significant costs.
A surface ejection-recuperation system with a nozzle is installed at the oil field. It mixes water and oil. The active medium is the fluid from the reservoir pressure maintenance system (RPM).
The resulting water-oil emulsion from the oil pipeline is passive. This allows you to reduce the pressure of production wells. The reliability of submersible equipment operation increases.
To prove the effectiveness of the proposed method, polytechnicians conducted numerical simulations of the system. Based on its results, they compiled a table of the effective use of technology. It shows the amount of water in the oil at the outlet of the apparatus. Water cut depends on the initial value of the same indicator in the well.
Scientists have found that the efficiency of the technology increases with increasing diameter of the nozzle of the ejection-recuperative system. The optimal option is with a diameter of 4 mm at a pressure at the inlet of the active medium of 8-11 MPa.
Next, the researchers selected an oil well where they conducted experiments. Practical tests of the developed technology were carried out in three operating modes. They differed in water pressure at the pump inlet, its flow rate, phase relationship and the diameter of the ejector nozzle.
Testing was carried out with a nozzle diameter of 4 mm and an active medium pressure of 8 MPa. It turned out that with an active phase flow rate of 69.6 cubic meters per day, the system allows reducing pressure by 0.3 MPa with closed annular valves. The pressure decreased by 0.1 MPa when the valves were open.
“By reducing the pressure on the installation by 0.3 MPa, it is possible to obtain an additional oil flow rate of 3.48 tons per day,” explains Alexander LEKOMTSEV, associate professor of the Department of Oil and Gas Technologies of PNIPU. – Therefore, the technology can be considered effective. This system is capable of reducing linear pressures at wells with the correct selection of operating conditions.” Thus, the efficiency of oil production can be increased by 5%.
