Journal of Petroleum Geology, Vol.4, No.1, pp. 89-101, 1981

©Copyright 2000 Scientific Press, Ltd.

PRIMARY PETROLEUM MIGRATION BY MOLECULAR SOLUTION: CONSIDERATION OF NEW DATA

Leigh C. Price*

*US Geological Survey, Box 25046, Denver, CO 80225, USA.

Abstract

Previous criticisms of primary petroleum migration by molecular solution have been: (1) the large compositional and molecular weight differences between hydrocarbons most readily dissolved in water and those found in crude oils, and (2) previously-measured aqueous petroleum solubilities were not high enough to account for petroleum deposits using reasonable geologic assumptions. New crude oil aqueous solubility data remove both of these criticisms. Above 275°C, with both increasing gas content and temperature, the solute hydrocarbons become compositionally more and more similar to, and eventually exactly match, the starting material. Mass balance calculations, using experimentally-measured crude oil solubilities, show that between 275° and 375°C, under realistic geologic assumptions, crude oil aqueous solubility is high enough to account for petroleum deposits. These new data also show that molecular solution is not a viable agent of primary petroleum migration below 275°C.