Abstract

Heat self-generating CO2 flooding is a new technique combining of steam flooding, gas flooding and so on. Its main mechanism is the application of steam heating self-generating gas agent solution to generate a large volume of gases (including CO2, NH3, etc) in the formation. While some of these gases acting with the crude oil to reduce the oil viscosity, some form miscible flooding to reduce oil/water interfacial tension, so as to achieve the purpose of enhancing heavy oil recovery. An optimized selection of the heat self-generating gas agents was performed. By comparison the difference before and after the reaction of the solution, the increase of alkaline is occurred after the reaction, which is helpful to reduce oil viscosity and lower interfacial tension. Studies indicate that heat-generating CO2 flooding technique can get a maximum viscosity reduction rate of 75.3%, oil/water interfacial tension decreased by 54.18%, and further improve the oil recovery by 4.6% based on the steam flooding, which shows a technical advantage to conventional enhancing oil recovery method. The pilot field shows that the technique can greatly improve the oil production, which will provide a powerful technical supporting for the efficient development of heavy oil.

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