Abstract: Source to Surface - A Model of Hydrocarbon Migration/Seepage

Martin D. Matthews

The Physical and Chemical Constraints on Migration from Source to Reservoir are Joined with the Spatial and Chemical Information Available from Surface Seepage to Better Understand the Process of Migration

The processes leading to hydrocarbon micro and macro seepage at the surface (tertiary migration) must obey the same physical laws followed by migration within the source rock (primary migration), from source to reservoir (secondary migration) and up the production string. Evidence indicates that the dispersed mechanisms are not effective in mass transport of hydrocarbon in the subsurface but are effective both in blurring or destroying hydrocarbon concentrations (source, reservoir, and along the route of migration). Evidence does, however support the importance of separate phase migration as a mechanism of migration.

The focused migration of hydrocarbons is considered as a rate process. The rate of generation of mobile hydrocarbons in a source rock and their rate of transport along the migration route must be greater than the loss of these hydrocarbons by dispersive mechanisms. The effects of the migration pathway are examined, particuarly the changing pressure and temperature effects and the lithologic hetrogeniety along the migration path.

AAPG Search and Discovery Article #90959©1995 AAPG Rocky Mountain Section Meeting, Reno, Nevada