乐安油田多期充注及生物降解作用对稠油黏度的影响分析  

Factors such as multi-stage charge mixing and biodegradation affecting the viscosity of heavy oil in the Le'an oilfield

作　　者：牛君[1] 黄海平[1,2] 蒋文龙[1] 李宁熙[1] 孙晶晶[1] 

机构地区：[1]中国地质大学(北京)能源学院,北京100083 [2]Department of Geoscience,University of Calgary,2500 University Drive NW

出　　处：《地球化学》2016年第5期441-450,共10页Geochimica

基　　金：国家自然科学基金(41273062)

摘　　要：乐安油田稠油黏度高,开采难度大。该区原油遭受严重生物降解作用以及多期次油气充注影响,原油黏度差别较大。运用有机地球化学方法,对乐安油田8口井所采的9件油样进行了生物标志物特征分析,以研究生物降解作用和后期油气充注对原油物性造成的影响。研究表明,原油组分受生物降解作用改造明显,生物降解级别至少在6级以上,但是最终的组成成分以及原油黏度主要受后期油气充注作用影响。25-降藿烷与正构烷烃系列共存、重排甾烷和规则甾烷以及藿烷与25-降藿烷系列绝对含量的变化关系均说明乐安油田的原油属于生物降解和多期充注共同作用的混合原油,其绝对含量与生物降解作用和油气多期充注作用密切相关,因此通过对该区稠油的形成及控制因素加以分析,可为以后稠油的生产开发打好基础。Heavy oil in the Le＇an oilfield is high in viscosity, hence its exploitation encounters many difficulties. And the viscosities vary significantly because of biodegradation and oil-charge mixing. Thus, it is necessary to systematically study the impact of biodegradation and oil-charge mixing by analyzing nine oil samples from different eight oil wells for their molecular compositions. The results have elucidated that biodegradation has a major impact on many classes of compounds, and the biodegradation scale has a major impact, at least, on 6 grades. However, the ultimate compositions and viscosities of heavy oils are influenced strongly by mixing with late oil charge, subsequent to the process of biodegradation. The oil samples have a complete series of n-alkanes and 25-norhopanes, and changes in the absolute contents of steranes and diasteranes and hopanes and 25-norhopanes reveal that mixing charging and biodegradation are collaborating to the oils from the Le＇an oil field The concentrations of biomarkers are closely related to mixing charging and biodegradation. Therefore, it can be used effectively to analyze the factors affecting multi-stage charge mixing and biodegradation of heavy oils, thus laying the foundation for developing heavy oils.

关 键 词：稠油 生物降解 油气充注 乐安油田 东营凹陷 

分 类 号：P593[天文地球—地球化学]