Oil & Gas Geology ›› 2003, Vol. 24 ›› Issue (1): 1-6,11.doi: 10.11743/ogg20030101

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CAUSATION OF PARTLY REVERSED ORDERS OF δ13 C IN BIOGENIC ALKANE GAS IN CHINA

Dai Jinxing, Xia Xinyu, Qin Shengfei, Zhao Jingzhou   

  1. Research Institute of Petroleum Exploration and Development, Petro China, Beijing
  • Received:2002-06-05 Online:2003-03-25 Published:2012-01-16

Abstract:

The δ13C values change in a regular manner with the increase of hydrocarbon gas molecular weight, i.e. change in normal order or reverse order.The normal order is δ13C113C213C313C4,and the reverse order is δ13C1> δ13C213C313C4.Partly reversed order is also common in gas samples from different basins in China,such phenomenon can be attributed to one or several of the following reasons:(a)Mixing of biogenic gas and abiogenic gas;(b)Mixing of gases from sapropelic sources and humic sources;(c)Mixing of gases from two source rock intervals of the same type but of different maturity;(d)Mixing of gases from one source rock interval of varying maturity.

Key words: biogenic alkane gas, carbon isotope, reverse, secondary gas, mixing gas, China

CLC Number: