Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5162750 | Organic Geochemistry | 2014 | 39 Pages |
Abstract
A total of 74 crude oils and condensates originating from various deposits were collected in Tarim, Junggar, Beibuwan and Bohai Bay basins and analyzed by comprehensive two dimensional gas chromatography-time of flight mass spectrometry (GCÂ ÃÂ GC-TOFMS) in order to investigate the occurrence and distributions of C9 and C10 hydrocarbons. 3-Ethyl-2-methylheptane and 1,1,2,3-tetramethylcyclohexane, two C10 compounds possibly derived from monoterpenoids via cracking and reduction, may be formed under anoxic conditions during diagenesis. We suggest that the ratio of 3-ethyl-2-methylheptane to 3-methylnonane (MT1) coupled with the ratio of 1,1,2,3-tetramethylcyclohexane to propylcyclohexane (MT2), are useful parameters to infer depositional environments and to distinguish oil families. The oils and condensates formed from source rocks deposited under anoxic conditions show high 3-ethyl-2-methylheptane and 1,1,2,3-tetramethylcyclohexane levels (both MT1 and MT2Â >Â 0.5). Whereas, the hydrocarbons derived from source rocks deposited in oxic conditions contain low amounts of 3-ethyl-2-methylheptane and 1,1,2,3-tetramethylcyclohexane (both MT1 and MT2Â <Â 0.5). These monoterpane parameters may be useful in petroleum exploration, especially for light oils and condensates where most high molecular weight biomarkers could be cracked or eliminated through fractionation.
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Physical Sciences and Engineering
Chemistry
Organic Chemistry
Authors
Guangli Wang, Bin Cheng, T.-G. Wang, Bernd R.T. Simoneit, Shengbao Shi, Peirong Wang,