Li B.,Key Laboratory of Exploration Technology for Oil and Gas Resources |
Huang G.-H.,Key Laboratory of Exploration Technology for Oil and Gas Resources |
Xu Y.-D.,Yangtze University |
Tang X.-Q.,Key Laboratory of Exploration Technology for Oil and Gas Resources |
Han J.-P.,Key Laboratory of Exploration Technology for Oil and Gas Resources
Bulletin of Mineralogy Petrology and Geochemistry | Year: 2011
The diversity and the complexity of the oils from the Tazhong area, Tarim Basin, are very rare. The analytical result shows that the maturation and the source rock phase are likely the secondary factors, while the main factor may be multi-stage deposit or secondary alteration in the reservoir. According to the board of the n-alkanes mole concentrations of the crude oil, this paper studied the distributions of n-alkanes' mole concentrations in crude oils from the different tectonic units in the Tazhong area, analyzed the degree of secondary alteration of the crude oil, and investigated the causes of evaporation fractionation and gas washing and their impacts to the chemical properties of the crude oils. The results indicated that, because of the factors of different migration channels and migration distance from the oil and gas sources, the frequencies of undergoing evaporative fractionation and gas washing decrease gradually but the frequency of finding crude oils increases from the No. 1 fault zone to the central uplift zone of the Tazhong area. The results also suggested that the forming of condensed oils and high wax oils in the No. 1 fault zone can be mainly associated with evaporative fractionation, gas washing and crystal fractionation.