The Colloidal Structure of Crude Oil and the Structure of Oil Reservoirs

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• 作者：Oliver C. Mullins ; Soraya S. Betancourt ; Myrt E. Cribbs ; Francois X. Dubost ; Jefferson L. Creek ; A. Ballard Andrews ; Lalitha Venkataramanan
• 刊名：Energy & Fuels
• 出版年：2007
• 出版时间：September 2007
• 年：2007
• 卷：21
• 期：5
• 页码：2785 - 2794
• 全文大小：411K
• 年卷期：v.21,no.5(September 2007)
• ISSN：1520-5029

文摘

Large sand bodies in the subsurface are shown to provide a unique laboratory for understanding both reservoirsand crude oils. Here, we treat the discovery by downhole fluid analysis of a gravitational concentration gradientof asphaltenes, the most dense component of crude oil, in a 2500-ft column of crude oil in the reservoir. Thecontinuous trend of crude oil properties across the field implies flow connectivity of this giant sand body,addressing the single largest uncertainty in the development of deepwater oil fields today-drainage area thatcan be achieved by each one of the extremely expensive wells. Consequently, downhole fluid analysis providesa new way to identify flow connectivity and to achieve significantly improved efficiency in oil production inhigh-cost arenas. In addition, detailed downhole and laboratory analyses of the asphaltene gravitational gradientshow that asphaltenes are dispersed in crude oils of this weight as nanoaggregates. This observation agreeswith the recently reported asphaltene nanoaggregates in toluene by high-Q ultrasonics and by NMR diffusionmeasurements. Finally, this case study suggests that resins are predominantly not associated with these asphaltenenanoaggregates, implying that the 70-year-old asphaltene-resin micelle model is in error. This asphaltene-resin micelle model, which has virtually no supporting data, appears to be substantially misleading in treatingasphaltene colloidal structure.