不同油品注空气氧化动力学特征

基于热分析技术确定稀油、普通稠油、特稠油3种油品注空气过程中4个反应阶段的温度区间,阐述不同油品在不同氧化阶段的氧化反应特征,根据动力学模型,采用微分法计算3种油品各反应阶段的氧化动力学参数。结果表明:低温阶段,稀油质量损失率最多,放热峰值最高,随着黏度增加,3种油品初始放热点升高,自燃点降低,高温氧化阶段特稠油放热峰为稀油的4.4倍;稠油相对稀油活化能整体偏高,低温氧化阶段活化能随着原油黏度增加而增加,高温氧化阶段活化能随着稠油黏度增加而减小;不同类型油藏可选择不同的注空气开发方式:轻质油藏低温氧化反应比高温燃烧更明显,推荐采用稀油注空气提高采收率,随着黏度增加,稠油油藏高温下放热峰值增加,更适合火驱开采实现高温氧化。

Kinetics characteristics of the oxidation for different oils in air injection process

Based on the thermal analyzing technique, the temperature ranges were determined during four reaction stages in the air injection process of thin oil, general heavy oil and extra-heavy oil, the oxidation reaction features were described for different oils at different oxidation stages. Based on the kinetic model, the differential method was employed to calculate the oxidation kinetic parameters of the three oils in different reaction stages. The results show that the thin oil has the most mass lost relative to the others in low temperature stage, while its exothermic value is the highest. With the rise of the viscosity, their initial hot spots increase, the spontaneous combustion points decrease, the exothermic peak of the extra-heavy oil is 4.4 times of the thin oil in high temperature oxidation stage;the heavy oil has pretty higher activation energy than the thin oil, with the increase of the crude oil viscosity, the activation energy increases in low temperature oxidation stage, while the activation energy decreases with the rise of the heavy oil viscosity in high temperature oxidation stage;for different types of the oil reservoir, the air injection developing methods can be selected as follows:the low temperature oxidation reaction is more obvious than high temperature combustion for the light oil reservoir, thus the thin-oil air injection is recommended to enhance the oil recovery, with the increase of the viscosity, the value of the exothermic peak increases in high temperature for the heavy oil reservoir, so in-situ combustion development is more suitable for high temperature oxidation.