Oxygen-reduced air flooding is a key technology for developing low-permeability reservoirs, fundamentally relying on the low-temperature oxidation (LTO) reaction between crude oil and oxygen. To elucidate the oil displacement mechanism and formulate efficient development strategies, it is essential to clarify the dynamic evolution pathways of crude oil components and intermediate products during this reaction. This study systematically investigated the oxidation reaction pathways and product evolution characteristics of light crude oil under low-temperature conditions by integrating thermogravimetric analysis, a selfdeveloped high-temperature and high-pressure oxidation apparatus, and gas chromatography–mass spectrometry. Combined with core displacement experiments, the study quantitatively evaluated how oxidation alters reservoir pore structure and its subsequent impact on ultimate oil recovery. The results reveal a significant oxidative aggregation and deposition phenomenon during the LTO process, occurring within a temperature window of 83.2–131.9 °C. The amount of deposition initially increases and then decreases with rising temperature, peaking at a specific temperature. The generated heavy components spontaneously accumulate within high-permeability zones, creating a self-deploying barrier. This barrier autonomously increases flow resistance precisely in these thief zones without external intervention, a process defined as the “autonomous profile control” effect. This mechanism, by differentially increasing flow resistance in high-permeability channels, intelligently reshapes the reservoir’s internal percolation field, promotes the transfer of displacement energy to low-permeability zones, and thereby significantly enhances microscopic sweep efficiency. Furthermore, a quantitative relationship model between deposition parameters and reservoir physical properties was established, achieving a comprehensive interpretation from microscopic reaction mechanisms to macroscopic oil displacement effects. These findings provide a theoretical basis and technical support for optimizing the oxygen-reduced air flooding process.
Li et al. (Mon,) studied this question.