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 s...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.展开更多
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.
文摘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.
