EHINGER, ROBERT F., Consulting Geologist, Tulsa, OK

ABSTRACT: Hydrocarbon Trap Classification Using a Tetrahedral Model

Creative exploration in mature areas also necessitates a new approach to classifying hydrocarbon traps. A literature review of hydrocarbon trap classifications yields a variety of systems based on genetic processes and/or geomorphic features. This paper does not introduce a new classification system, but integrates the commonly accepted trapping mechanisms into a coherent modern model. The proposed system depicts hydrocarbon traps ascomposed of one to four components: Structural, Stratigraphic, Diagenetic, and Hydrodynamic. By visualizing these four components as end-members plotted at the corners of a tetrahedron (akin to the SiO tetrahedron), virtually all known traps can be accommodated. The Diagenetic component is unique because it can be trap-sealing or trap-enhancing and can be asily overlooked during early exploration programs. For most areas, the vast majority of the traps would plot along the structural-stratigraphic axis usually with some diagenetic component. The tetrahedral model indicates that other analogs should also exist along the structural-diagenetic axis, and more rarely along the structural-hydrodynanic axis. Because the diagenetic and hydrodynamic components tend to be subtle, they can be obscured by the emphasis placed primarily on the structural and stratigraphic components. The tetrahedral model helps focus the geologist's attention on all the components of a specific trap and this is the main thrust of this paper.

AAPG Search and Discovery Article #90987©1993 AAPG Annual Convention, New Orleans, Louisiana, April 25-28, 1993.