A Process for Primary Migration of Petroleum

Abstract

Experimental data support a model migration process in which dioxide and hydrocarbon gases are produced in source rocks and are dissolved in pore water concurrently with oil generation. The dissolved gases mobilize the liquid hydrocarbons so that they can leave the source rock with any water expelled during compaction. In noncompacting situations the liquid hydrocarbons can diffuse over reasonable distances from their source rocks into adjacent permeable beds. They later phase-separate by removal of dioxide from the water in or near a reservoir or en route to a reservoir. Removal of dioxide is accomplished by reaction with carbon dioxide-starved or unconditioned sedimentary rocks as the oil-bearing water moves up faults and permeable strata, or by e solution due to low pressure at shallow depths.