Nanoaggregates of Asphaltenes in a Reservoir Crude Oil and Reservoir Connectivity

Autor: Alan G. Marshall, Diane Bustamante, Oliver C. Mullins, G. Todd Ventura, Andrew E. Pomerantz, Christopher M. Reddy, Robert K. Nelson, Jeremiah M. Purcell, Soraya S. Betancourt, Gene Monson, Julian Zuo, Francois Xavier Dubost, Oswaldo Viloria, Ryan P. Rodgers
Rok vydání: 2008
Předmět:
Zdroj: Energy & Fuels. 23:1178-1188
ISSN: 1520-5029
0887-0624
DOI: 10.1021/ef800598a
Popis: Recently, asphaltenes have been shown to form nanoaggregates in toluene at very low concentrations (10−4 mass fraction). Subsequently, in situ analysis of a 3000 ft vertical column of crude oil by downhole fluid analysis (DFA) indicated that the asphaltenes in a black crude oil exhibit gravitational sedimentation according to the Boltzmann distribution and that the asphaltene colloidal size is ∼2 nm. Here, we perform a follow-up study of a reservoir black oil from a different field. The black oil in a 658 ft vertical column is analyzed by DFA and advanced laboratory analytical chemical methods. An asphaltene colloidal particle size is found to be ∼2 nm according to the Archimedes buoyancy term in the Boltzmann distribution. In addition, an equation of state (EoS) approach based on literature critical constants and molecular weights for asphaltenes gives an aggregation number of ∼8. Molecular compositional similarities between different oil samples were established with comprehensive two-dimensional gas ch...
Databáze: OpenAIRE