Reservoir morphology can be predicted by interpretational of depositional environments in cored sections by means of the vertical sequence of sedimentary structures, composition, and texture. When cores or samples are not available, the vertical change in porosity and permeability may reflect grain size and compositional changes. Reservoir morphologies are illustrated by field studies of (1) fluvial sandstones in point bars and braided channels, (2) deltaic sections with fluvial channel or delta-destructional reservoir, (3) barrier bars and longshore bars, (4) shallow-marine sandstones, and (5) deep-water turbidite reservoirs. In each case, the relation of reservoir sandstones to the adjacent trap facies is clearly indicated by subsurface control.

Effectiveness of trap facies can be calculated if the rock and fluid properties are known or can be estimated for reservoir conditions. Oil-column calculations show that a trap facies may be porous and permeable, yielding a significant quantity of water on test, and yet form an effective seal to oil columns of 50 to 75 ft. Oil trapped by capillary pressures in barrier facies can be augmented by down-dip hydrodynamic flow. By the integration of all interpretations, reservoir, trap and fluid pressures, stratigraphic oil columns can be evaluated quantitatively.