杨鹏程, 李浩, 刘峰, 李倩. 西湖凹陷X构造凝析油与蜡质油的形成机制[J]. 海洋地质与第四纪地质, 2019, 39(6): 177-187. DOI: 10.16562/j.cnki.0256-1492.2019070405
引用本文: 杨鹏程, 李浩, 刘峰, 李倩. 西湖凹陷X构造凝析油与蜡质油的形成机制[J]. 海洋地质与第四纪地质, 2019, 39(6): 177-187. DOI: 10.16562/j.cnki.0256-1492.2019070405
YANG Pengcheng, LI Hao, LIU Feng, LI Qian. Formation mechanism of condensate oil and waxy oil in Structure X of Xihu Depression[J]. Marine Geology & Quaternary Geology, 2019, 39(6): 177-187. DOI: 10.16562/j.cnki.0256-1492.2019070405
Citation: YANG Pengcheng, LI Hao, LIU Feng, LI Qian. Formation mechanism of condensate oil and waxy oil in Structure X of Xihu Depression[J]. Marine Geology & Quaternary Geology, 2019, 39(6): 177-187. DOI: 10.16562/j.cnki.0256-1492.2019070405

西湖凹陷X构造凝析油与蜡质油的形成机制

Formation mechanism of condensate oil and waxy oil in Structure X of Xihu Depression

  • 摘要: X构造的原油按照物性的差异主要分为两类:第一类为凝析油,具有密度低、含蜡量低的特点;第二类为蜡质油,具有密度中等、含蜡量高的特点。为了明确原油物性差异的原因,对原油的地球化学特征进行了深入分析,发现这两类原油的饱和烃色谱存在明显的差异,但甾烷特征、萜烷特征以及碳同位素特征又比较相似,表现出同源的特点,推测次生作用是原油物性差异的主要原因。对这两类原油的轻烃色谱以及指纹参数进行了精细对比,发现:①凝析油和蜡质油的全烃色谱存在镜像关系;②凝析油的庚烷/甲基环己烷(石蜡度)偏高,甲苯/正庚烷(芳香度)偏低,蜡质油则相反;③凝析油和蜡质油的正构烷烃nCm+1/nCm存在协变关系,且凝析油的数值更大。认为X构造原油遭受了气侵,凝析油是蒸发分馏的产物,而蜡质油则是蒸发分馏的残留油。

     

    Abstract: Oil in the Structure X of the Xihu Depression can be divided into two groups based on the differences in physical properties. One is the condensate oil, which is characterized by low density and low wax content; and the other is the waxy oil, which is characterized by medium density and high wax content. Geochemical characteristics of crude oil were studied in details in order to define the causes of the differences. It is so obvious that there are great differences between condensate oil and waxy oil in saturated hydrocarbon chromatography characters. However, the characteristics of sterane, terpane, and carbon isotope of condensate oil are as the same as the waxy oil. It means that they come from same source, and secondary alteration is the real cause to the difference in physical properties. Detailed correlation of lighter hydrocarbon chromalogram and fingerprint parameters the two oils suggest the following: (1) There is a mirror image relationship of total hydrocarbon chromatography between condensate oil and waxy oil. (2) Condensate oil is characterized by high index of nC7/MCyC6 and low index of Tol/nC7, whereas waxy oil shows an opposite pattern. (3) There are covariant relation of the index of nCm+1/nCm of N-alkanes between the condensate oil and the waxy oil, suggesting that oil has suffered from gas invasion. The condensate is the results of evaporative fractionation, and the waxy is the remainder.

     

/

返回文章
返回