A method of injecting foamy air and oxygen-enriched pyrolysis thermochemical composite air flooding into the oil layer

Abstract

The invention discloses a method for extracting oil by injecting foam air and oxygen-enriched pyrolysis thermochemcial composite air into an oil reservoir in a flooding mode. The method comprises the steps that in the first injection step, a foaming agent is injected into the oil reservoir so as to generate foam; in a second injection step, an oxygen-enriched air mixture is injected subsequently, and ignition is conducted on a stratum; and subsequently, the air is injected for oil displacement production. Large pore paths can be blocked by the foam, water is blocked while oil is not blocked, and hypertonic pore paths are sealed; and since the foam and the air are alternately injected, gas channeling can be effectively prevented, the purposes of modifying and flooding can be achieved, residual oil can be better displaced, communication of areas unswept by injected water is achieved, and the crude oil displacement and sweeping efficiency are improved. The foaming agent is an anionic surfactant with high activity, and can be used for lowering oil-water interfacial tension greatly, improving the wettability of the surface of rock and improving the displacement efficiency of an injectant, and accordingly the purpose of increasing the recovery ratio is achieved. Advantages of the technologies of foam flooding and air flooding are fully achieved, the sweeping coefficient is increased more efficiently, and the displacement efficiency is improved more efficiently.

Description

technical field [0001] The invention relates to an oil recovery technology of injecting foamy air and oxygen-enriched high-temperature pyrolysis thermochemical composite air flooding into an oil layer, belonging to the field of oil recovery engineering. Background technique [0002] Foam fluid has been used in oilfields for more than 40 years at home and abroad. In order to prevent premature gas channeling caused by too low viscosity of gas injection in the initial foam flooding, it was simply treated with oily agent aqueous solution, but in In practice, due to the poor stability of conventional foam, its popularization and application are hindered. Air foam flooding technology is a new technology for tertiary oil recovery developed on the basis of conventional foam flooding and air injection. Its main principle is that air injection During air flooding, low-temperature oxidation reaction occurs, tail gas is generated, and multi-phase miscible gas flooding is formed. In addi...

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Problems solved by technology

[0002] Foam fluids have been used in oil fields for more than 40 years at home and abroad. In order to prevent premature gas channeling caused by too low viscosity of gas injection, the initial foam flooding was simply treated with an aqueous solution of oily agent, but in In practice, due to the poor stability of conventional foam, its popularization and application are hindered. Air foam flooding technology is a new technology for tertiary oil recovery developed on the basis of conventional foam flooding and air injection. Its main principle is that air injection During air flooding, low-temperature oxidation reaction occurs, tail gas is generated, and multi-phase miscible gas flooding is formed. In addition to the oil displacement mechanism of conventional foam, the air-foam composite flooding technology also has the effect of low-temperature oxidation during air flooding. This new technology concentrates The dual advantages of air flooding and ordinary foam flooding can not only significantly increase the swept volume of the oil layer, but also improve the oil displacement efficiency after water washing, thereby greatly improving the recovery rate, which has high research value in theory and practice. Very guiding value, more and more people's attention in recent years

[0003] The half-life of the existing foam fluid is relatively short, only 48 hours, and the plugging effect of gas channeling in oil production wells is not good

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