Tetrahedral Model for Hydrocarbon Trap Classification: An Aid to Prospect Generation

Robert F. Ehinger

To become more creative in prospect generation, the geologist needs to know the various mechanisms that produce hydrocarbon traps. A review of hydrocarbon trap classifications from the geologic literature yields a variety of systems based on genetic processes and/or geomorphic features. This paper will not introduce a new classification system but will integrate the commonly accepted trapping mechanisms into a coherent model. The proposed system depicts hydrocarbon traps as composed of one to four components: structural, stratigraphic, diagenetic, and hydrodynamic. By visualizing these four components as end members plotted at the apexes of a tetrahedron, one can easily describe virtually all known traps. The diagenetic component is special because it can be trap sealing r trap enhancing. For the Mid-Continent, most traps would plot along the structural-stratigraphic axis usually with some diagenetic component. The tetrahedral model indicates other analogs may similarly exist along the structural-diagenetic axis and more rarely along the structural-hydrodynamic axis. Because the diagenetic and hydrodynamic components tend to be subtle, one can easily overlook them in prospect generation. Avoiding this oversight is one of the advantages of the proposed three-dimensional system.

AAPG Search and Discovery Article #91025©1989 AAPG Midcontinent, Sept. 24-26, 1989, Oklahoma City, Oklahoma.