傅里叶变换离子回旋共振质谱技术在稠油高低温氧化评价中的应用

为了认识稠油开发过程中低温氧化与高温氧化阶段原油变化规律,利用静态氧化釜开展稠油的高低温氧化实验,借助傅里叶变换离子回旋共振质谱分析技术对高低温氧化前后的原油分子量及O、N、S杂原子化合物特征开展研究,结果表明：原油低温氧化阶段分子量分布特征与原样相似,分子量分布范围在m/z 200至m/z 750,整体呈平缓状单峰型分布,高温氧化阶段分子量分布范围前移,呈明显的前峰单峰型分布；杂原子化合物中的O元素在低温氧化阶段主要以无环的饱和二元酸形式存在,在高温氧化阶段受环化、芳构化及脱甲基作用的影响,伴随着侧链烷基及杂原子基团的断裂和芳构化过程,造成原油中杂原子化合物向着碳数更小、DBE值更低的方向演化。该研究探索了温度与原油结构及化学组成之间的关系,对于指导稠油开发现场具有重要意义。

Application of Fourier Transform Ion Cyclotron Resonance Mass Spectrometry in Assessing High- and Low-Temperature Oxidation of Heavy Crude Oil

To understand the changes in crude oil during low-temperature and high-temperature oxidation stages in the development of heavy oil, static oxidation vessels were used to conduct high- and low-temperature oxidation experiments on heavy oil. By utilizing Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) analysis technology, the molecular weight and characteristics of oxygen, nitrogen, and sulfur impurity compounds in the crude oil before and after high- and low-temperature oxidation were studied. The results showed that the molecular weight distribution characteristics of the crude oil during the low-temperature oxidation stage were similar to those of the original sample, with a distribution range from m/z 200 to m/z 750, presenting a gentle single-peak distribution. During the high-temperature oxidation stage, the molecular weight distribution range was shifted forward, presenting a distinct front peak single-peak distribution. In the impurity compounds containing oxygen, the element was mainly present in the form of noncyclic saturated diacids during the low-temperature oxidation stage. However, during the high-temperature oxidation stage, it was influenced by cyclization, aromatization, and demethylation, accompanied by breakage and aromatization of side chain alkyl and impurity group, resulting in the evolution of impurity compounds in crude oil towards a direction with fewer carbon numbers and lower DBE values. This study explored the relationship between temperature and crude oil structure and composition, which is of great significance for guiding the field development of heavy oil.