岩屑存在下油藏注空气原油的氧化热解分析

Oil Oxidation Pyrolysis Analysis of Oil Reservoir Air Injection in the Presence of Cutting

采用静态氧化管实验结合热分析方法（TG/DTG/DTA）分别从原油氧化速率、组分变化及热重放热角度,考察了油藏岩屑存在下原油氧化热解特性及反应机理.并通过TG/DTG/DTA分析测试结果与多孔介质中原油氧化实验的结论进行对比分析,判断两种方法用于原油氧化热解机理研究方面是否具有一致性.结果表明,黏土对原油氧化有较好的催化效果,其含量越高,原油耗氧速率和碳键剥离速率越大;氧化反应后,原油中重组分（C22＋）含量降低,中、轻质组分（C7~21）含量上升;热重分析显示,原油经历了低温氧化、燃料沉积及高温氧化3个阶段;原油在低温氧化阶段一般呈现吸热趋势,质量损失越高,吸热量越大.

In order to expand the enhanced oil recovery （EOR） technology of air injection to light oil reservoir, experiments were conducted using static oil oxidation tube and by thermal analysis methods such as TG/DTG and DTA. The oxidation pyrolysis characteristics and oxidation reaction mechanism of crude oil in the presence of cutting were analyzed from the perspectives of crude oil oxidation rate （relative oxygen consumption rate and relative carbon bond broken rate）, change of crude oil components, thermogravimetry and heat release. At last, the results ol thermal analysis methods and static oil oxidation tube experiment in porous media were compared to ascertain whether the two methods are consistent in low temperature oil oxidation mechanism, aiming at comparing and analyzing the similarities and differences of the two researching methods. Results show that clay has a good catalytic effect on crude oil oxidation. The higher the content of clay in cutting is, the greater the rate of oxygen consumption and carbon bond peeling will be. Besides, the content of heavy fractions （C22＋）in crude oil decreases while that of middle and light fractions （C7-21）in crude oil increases after several days＇ oxidation reaction. Thermal analysis results show that oil undergoes low-temperature oxidation, fuel deposition and high-temperature oxidation. Clay in reservoir cutting plays a catalytic role during oil oxidation reaction. Crude oil generally shows an endothermic trend at low-temperature stage, and the higher the mass loss, the greater the heat absorption. It is shown that, in some cases the understand-ing from the study of oil oxidation, cracking and combustion mechanism by using qualitative oxidation kinetics analysis methods （TG/DTG/DTA） is consistent with the conclusion from low-temperature oil oxidation experiment in porous media.