Low-temperature oxidation patterns and thermodynamics in light oil reservoirs under air injection

doi:10.3969/j.issn.1006-6535.2025.06.011

Abstract

Abstract: Addressing the unclear patterns of low-temperature oxidation(LTO)and high safety risks of conventional air flooding in light oil reservoirs during high-pressure air injection,this study took the Xinjiang X reservoir as an example.Using static isothermal oxidation tube experiments and non-isothermal thermogravimetric analysis(TG/DTG-DTA),combined with chromatography,infrared spectroscopy,physical property measurements,and the classical Arrhenius kinetic model,analysis was done from a microscopic perspective about the changes in crude oil hydrocarbon molecular structure and oxidation characteristics during oxidation.Results showed that the main LTO reactions of the crude oil were oxygen-addition,polycondensation,and C-C bond scission.Increasing oxygen concentration and the heterogeneous catalytic effect of reservoir rock facilitated LTO,deepening oxidation and generating more fuel-grade residue precursors.Crude oil in 13% O₂ depleted air still exhibited high oxidation reactivity and strong fuel-residue generation capacity,and the presence of clay minerals and active metal elements in the reservoir rock indicated great potential for implementing oxygen-depleted air injection in the Xinjiang X reservoir.This study provides positive guidance and theoretical support for implementing oxygen-depleted air flooding in high-clay-content light oil reservoirs.

Key words: light oil reservoir, high-pressure air injection, low-temperature oxidation, oxidation pattern, sensitivity analysis, thermodynamics

CLC Number:

TE341

LIU Penggang. Low-temperature oxidation patterns and thermodynamics in light oil reservoirs under air injection[J]. Special Oil & Gas Reservoirs, 2025, 32(6): 92-99.

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