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Recognition of the turbidite nature of many petroleum-producing sands worldwide makes it imperative to understand both the facies types encountered and the trap types to be anticipated in future exploration and development work. Several facies models have been proposed, most of which are not readily usable with the data generally available in subsurface work. The facies analysis presented examines large-scale controls, such as climate, provenance, basin geometry, and tectonics, and then considers the various large to small-scale facies and sand-body geometries that result. Use of wire-line log pattern, dipmeter, and core descriptive data as criteria is emphasized. The newly recognized meander channel facies is shown to be important in prograded muddy slope areas. The concept of a "fac es" as referring to a mappable assemblage of beds of varying natures and origins is favored, in contrast to the practice of assigning a separate facies designation to each single successive bed, with resulting uncertainty as to overall significance.

The author's trap-type classification, which includes canyon-dependent, fan-dependent, anticline-dependent, fault-dependent, and uplift topography-dependent traps, is used in conjunction with the facies analysis to predict the trap types most likely to be encountered in the various facies and basin settings. The trap classification itself is developed as a predictive tool rather than as a pigeonholing exercise.

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