Applications of Reservoir Geochemistry to Migration Studies: An Exploration Perspective

Steve Larter, Dag Karlsen, Idar Horstad

Petroleum correlation studies are routinely used to define regional oil family relationships and to define source rock/oil relationships. These methods, usually based on fingerprint gas chromatograph and mass spectrometer methods of selecting fractions of oils or source rock bitumens, are rarely applied to detailed examination of in-field variations in petroleum composition. Petroleum traps are integrators of the evolving petroleum charge expelled from source rocks increasing in maturity with time. Thus a given trap sees progressively more mature (and compositionally different) petroleum as the source-conductor-trap system subsides. Lateral heterogeneities in petroleum columns can be documented, resulting from the inability of diffusive or advective processes to homogenize petroleum column composition at large ranges over geological times. The description of these lateral and vertical petroleum column heterogeneities can be used to define source rock basin configurations and to place restrictions on the volume of conductor beds accessing the trap. Examples are shown from northwestern Europe in which petroleum geochemical variations in petroleum columns are used to provide information for the explorationist.

AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.