稠油富氧燃烧机理及不同含氧量下的动力学参数

Mechanism of Oxygen-enriched Combustion of Heavy Oil and Kinetic Parameters under Different Oxygen Contents

郭 雯 邬青鑫 唐君实 关文龙 袁士宝

GUO Wen WU Qingxin TANG Junshi GUAN Wenlong YUAN Shibao

稠油富氧火驱是一种增强型火烧油层技术，通过注入高浓度氧气能有效提高稠油燃烧效率，但关于稠油富氧燃烧机理及不同含氧量下的动力学参数研究较少。为明确富氧对稠油火驱氧化特性的影响，以辽河稠油为例，利用同步热分析仪研究了不同氧气浓度和升温速率条件下的稠油氧化热失重以及放热等特性变化，基于等转化率法计算不同转化率、不同氧气浓度下的活化能，进而利用数值模拟研究了富氧对火驱的改善效果。结果表明，富氧环境下稠油氧化仍可划分为低温氧化前、低温氧化、焦炭沉积和高温氧化4个阶段。随着氧气加量由20%增至100%，氧化反应更加强烈，反应速率更大，放热量升高，对应的焦炭沉积阶段提前20 ℃。不同氧气加量下活化能的变化趋势相同，在低温氧化阶段氧气浓度对活化能的影响较小，但高温氧化阶段响应剧烈，活化能降低15～25 kJ/mol。在相同氧气浓度下，升温速率增加会导致热滞后现象。数值模拟研究验证了富氧条件可有效提高火驱燃烧效果。当氧气加量由 30%增至 50%时，累积产油量增幅为 11 234 m3；氧气加量由 70%增至 100%时，累积产油量增幅（3753 m3）较小，推荐采用50%～70%的氧气作为富氧火驱注入气。随着氧气浓度的增加，前缘温度（350～450 ℃）增加，提高了燃烧的稳定性，改善了常规火驱燃烧效果。

Heavy oil oxygen-enriched fire flooding is an enhanced in-situ combustion technology，which can effectively improve the combustion efficiency of heavy oil by injecting high concentration oxygen. However，there are few studies on the mechanism of heavy oil oxygen-enriched combustion and the kinetic parameters under different oxygen contents. In order to clarify the effect of oxygen enrichment on the oxidation characteristics of heavy oil in-situ combustion，Liaohe heavy oil was taken as an example. The simultaneous thermal analyzer was used to study the thermal weight loss and exothermic characteristics of heavy oil oxidation under different oxygen concentrations and heating rates. Based on the iso-conversional method，the activation energy under different conversion rates and different oxygen concentrations was calculated，and then the improvement effect of oxygen enrichment on in-situ combustion was studied by numerical simulation. The results showed that the oxidation of heavy oil under oxygen-rich environment could still be divided into four stages：pre-low temperature oxidation，low temperature oxidation，coke deposition and high temperature oxidation. With the increase of oxygen dosage from 20% to 100%，the oxidation reaction was more intense，the reaction rate was larger，the heat release increased，and then the corresponding coke deposition stage was advanced by 20 ℃. The change trend of activation energy under different oxygen concentrations was the same. In the low temperature oxidation stage，the oxygen concentration had little effect on the activation energy. While in the high temperature oxidation stage，the response was intense，and then the activation energy was reduced by 15—25 kJ/mol. At the same oxygen concentration，the increase of heating rate would lead to thermal hysteresis. The numerical simulation study verified that the oxygen-enriched condition could effectively improve the combustion effect of fire flooding. When the oxygen dosage increased from 30% to 50%，the cumulative oil production increased by 11 234 m3. When the oxygen dosage increased from 70% to 100%，the cumulative oil production increased by 3753 m3. It was recommended to use 50%—70% oxygen as the injection gas of oxygen-enriched fire flooding. With the increase of oxygen concentration，the leading edge temperature（350—450 ℃）increased，which improved the stability of combustion and the combustion effect of conventional fire flooding.

10.19346/j.cnki.1000-4092.2025.01.017