低渗透油藏空气驱原油氧化机理实验

为深入探究低渗透油藏空气驱开发过程中原油的氧化特征及其影响因素,评价其驱油效果,以新疆油田低渗透油藏为研究对象,开展原油组分分析、原油氧化特征、空气驱及空气泡沫驱等实验,系统研究了不同条件下原油氧化特征及规律。实验结果表明:相同条件下,油砂比纯油样静态氧化反应速率大,反应充分,且反应速率与反应压力、温度、作用时间呈正相关;油藏温度下,原油经历氧化反应后轻重比减小,主峰碳增加;反应温度对空气驱原油动态氧化特征有较大影响,温度越高耗氧量越大,反应越充分;空气驱具有较好驱油效果,但易发生气窜;泡沫驱可有效封堵气窜通道,扩大空气波及体积,改善空气驱效果。研究成果对空气驱理论研究及应用具有借鉴意义。

Experiment on Oxidation Mechanism of Crude Oil by Air Flooding in Low permeability Reservoirs

In order to deeply investigate the oxidation characteristics of crude oil and its influencing factors during the development by air flooding of low permeability reservoirs and evaluate its oil displacement efficiency, experiments on crude oil component analysis, oxidation characteristics of crude oil, air flooding and air-foam flooding were conducted to systematically study the oxidation characteristics and laws of crude oil under different conditions, taking the representative reservoirs of low permeability in Xinjiang Oilfield as the study object. The experimental results showed that, under the same conditions, the static oxidation reaction rate of oil sand was higher than and the reaction was more sufficient than that of pure oil sample, and the reaction rate was positively correlated with the reaction pressure, temperature and action time; at the reservoir temperature, the weight ratio of crude oil after oxidation reaction decreased, and the main peak carbon increased; the reaction temperature had a great influence on the dynamic oxidation characteristics of crude oil in air flooding, the higher the temperature, the greater the oxygen consumption and the more sufficient the reaction; the air flooding was effective in oil displacement, with gas channeling easy to occur; the foam flooding could effectively block the gas channeling channel, expand the air swept volume, and improve the air flooding effect. The study results have an exemplary significance regarding the theoretical research and application of air flooding.