A new set of diagrams aids in analyzing fault juxtaposition and sealing. The diagrams are based on the interaction of rock lithology and the fault displacement (throw) magnitude to control juxtapositions and fault seal types. The advantages of the diagrams are that they allow an evaluation of a fault seal without the need for detailed three-dimensional mapping of stratigraphic horizons and fault planes, and can be used to contour permeability, sealing capacity, and transmissibility of fault zones. These diagrams may be used to rapidly identify the critical fault throw and juxtapositions that require mapping to identify compartments in hydrocarbon reservoirs.