High molecular weight (C_(35)^+) n-alkanes of Neogene heavily biodegraded oil in the Qianmiqiao region,North China  

作　　者：WANG Tieguan (T.-G. WANG), ZHU Dan, ZHANG Zhihuan, LU Hong & YANG ChiyinKey Laboratory of Petroleum Entrapment Mechanism of the Ministry of Education, University of Petroleum, Beijing 102200, China Guangzhou Institute of Geochemistry, Chinese Academy of S 

出　　处：《Chinese Science Bulletin》2002年第16期1402-1407,共6页

基　　金：This work was supported by the National Natural Science Foundation of China (Grant No. 40172056);the Research Found for the Doctoral Program of High Education (RFDP No. 2000042506);the Geological Research Institute, Dagang Oilfield (Group) Co. Ltd.

摘　　要：With wax content of 1.62%, heavy oil has been produced from the sandstone reservoirs of Neogene Guantao Formation (Ng1m). In the GC and GC-MS RIC profiles of its aliphatic fraction, n-alkanes are totally lost, which shows the result of heavy biodegradedation. However, the remaining trace C13-C36 n-alkanes can be still seen from its mlz 85 mass chromatogram. In addition, a complete series of C35-C73 high molecular weight (HMW) n-alkanes was detected by high-temperature gas chromatography (HTGC). The HMW R-alkane series shows a normal distribution pattern, a major peak at nC43, obvious odd-carbon-number predominance, CPI37-55 and OEP45-49 values up to 1.17 and 1.16-1.20 respectively. The present study not only has conformed the strong resistibility of HMW n-alkanes to biodegradation in crude oils as concluded by previous researchers, but also has provided some significant information on source input and maturity for the heavily biodegraded oil in the Qianmiqiao region.With wax content of 1.62%, heavy oil has been produced from the sandstone reservoirs of Neogene Guantao Formation (NglIII). In the GC and GC-MS RIC profiles of its aliphatic fraction, n-alkanes are totally lost, which shows the result of heavy biodegradedation. However, the remaining trace C13-C36 n-alkanes can be still seen from its mlz 85 mass chromatogram. In addition, a complete series of C35-C73 high molecular weight (HMW) n-alkanes was detected by high-temperature gas chromatography (HTGC). The HMW n-alkane series shows a normal distribution pattern, a major peak at NC43, obvious odd-carbon-number predominance, CPI37-55 and OEP45-49 values up to 1.17 and 1.16-1.20 respectively. The present study not only has conformed the strong resistibility of HMW n-alkanes to biodegradation in crude oils as concluded by previous researchers, but also has provided some significant information on source input and maturity for the heavily biodegraded oil in the Qianmiqiao region.

关 键 词：biodegradation heavy oil high-temperature gas chro-matography (HTGC) high molecular weight (HMW) WAX fraction HMW n-alkane. 

分 类 号：P618.13[天文地球—矿床学]