新疆C油田注空气提高采收率可行性研究

空气驱是一种新型的提高采收率技术，其独特的低温氧化反应能够在地层中放热活化原油。本文针对新疆C油田原油开展了低温氧化实验和绝热氧化实验，通过分析氧化后油气组分来研究压力对低温氧化和绝热氧化反应的影响，揭示原油氧化反应机理，同时利用长岩心空气驱物理模拟实验对比分析了空气驱和水驱后空气驱复合驱对驱油效率的影响规律。研究结果表明，氧化压力增大可有效改善原油低温氧化进程，增强原油氧化活性，原油耗氧能力增强，氧加成反应也更明显，原油中质和重质组分增加。原油绝热氧化积聚的热效应能显著提高原油氧化效果，导致原油耗氧量增加，脱羧反应生成CO和CO2量也显著增加，高压条件下CO和CO2的生成量增加53.6 %，各组分变化更为明显。空气驱过程中，空气与原油反应，在烟道气驱、混相驱和原油膨胀等多重机理作用下，长岩心驱油效率可达40.17 %。与空气驱相比，水驱后空气驱复合驱驱油效率更高，当注入压力为36 MPa时，复合驱驱油效率为51.44 %。

Feasibility Study of Air Injection to Improve Oil Recovery in Xinjiang C Oilfield

High pressure air injection is a novel enhanced oil recovery technique due to massive heat released by low temperature oxidation reaction to active crude oil. A low-temperature oxidation experiment and adiabatic oxidation experiment were carried out for the crude oil in Xinjiang C Oilfield. The influence of pressure on low-temperature oxidation and adiabatic oxidation reactions was studied by analyzing the oil and gas components after oxidation, and the mechanism of the oxidation reaction of crude oil was revealed. At the same time, long core air flooding physical simulation experiments were used. The influence of air flooding and combined flooding after water flooding on oil displacement efficiency is comparatively analyzed. The research results show that the increase of oxidation pressure can effectively improve the low-temperature oxidation process of crude oil, enhance the oxidation activity of crude oil, increase the oxygen consumption capacity of crude oil, increase the oxygen addition reaction, and increase the intermediate and heavy components of crude oil. The thermal effect of adiabatic oxidation of crude oil can significantly increase the oxidation effect of crude oil, which leads to an increase in the oxygen consumption of crude oil. The amount of CO and CO2 generated by decarboxylation reaction also increases significantly. The generation of CO and CO2 under high pressure conditions increases by 53.6 %, and the changes in each component are more severe obvious. During the air flooding process, air reacts with crude oil. Under the action of multiple mechanisms such as flue gas flooding, miscible flooding and crude oil expansion, the long core flooding efficiency can reach 40.17 %. Compared with air flooding, the combined flooding efficiency of air flooding is higher after water flooding. When the injection pressure is 36 MPa, the combined flooding efficiency is 51.44 %. Keywords: low temperature oxidation; adiabatic oxidation; component; air drive; Oil displacement efficiency