Hydrocarbons in micellar solution

Micelles are molecular aggregates formed in solutions of surface-active agents (surfactants compounds that orient at an interface such as between oil and water) (McAulifFe, 1980). Micelles may contain up to 100 or more surfactant molecules with a nonpolar (hydrophobic) end on the inside and a polar (hydrophilic) end on the outside. In 1959, Baker first advanced the concept of solubilization of hydrocarbons in (soap) micelles as a possible primary migration mechanism. The possible role of soaps, i.e. salts of organic acids, in primary migration was supported by Cordell (1973). The concept was considered attractive because it also explains how the practically water-insoluble hydrocarbons can solubilize in groundwater at relatively low temperatures. However, the likelihood of micellar solution as an effective primary migration mechanism has been seriously questioned by many authors (for instance Price, 1976 Hunt, 1979 Tissot and Welte, 1984). The main problems associated with micellar solution are  

Micelles appear to be larger than the small size of the pore throats in the source rock at a depth of burial corresponding to the main zone of oil and gas generation. According to Tissot and Welte (1984), primary migration of hydrocarbons in micellar solution would definitely be limited down to a depth of about 2000 m. 

In addition, the concentration of potential micelle-formers will decrease with depth of burial of the source rock (as the generation of nitrogen, sulfur and oxygen polar compounds, which are more likely to form micellar solution, decreases with increasing depth). 

the role of micellar solution of hydrocarbons in primary migration can be considered to be limited. 

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M. Baviere and T. Rouaud. Solubilization of hydrocarbons in micellar solutions Influence of structure and molecular weight (solubilisation des hydrocarbures dans les solutions micellaires influence de la structure et de la masse moleculaire). Rev Inst Franc Petrol, 45(5) 605-620, September-October 1990. 

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