Sand Bodies and Sedimentary Environments: A Review

Knowledge of sand-body morphology may help to solve many practical exploration problems. Knowledge of the environment of deposition is required to predict sand-body morphology most successfully. This paper briefly reviews sand-body nomenclature, discusses the problems of representation by cross sections, comments on currently popular concepts of sedimentary environments, and summarizes in detail what is known of sand-body characteristics in six major environments: alluvial, tidal, turbidite, barrier island, shallow-water marine, and desert eolian. The characteristics of alluvial, tidal, and barrier-island sand bodies are better known than those of turbidite, shallow-water marine, and desert-eolian ones. Nonetheless, there is an obvious lack of systematic, quantitative data on the petrology, texture, sedimentary structures, and internal organization of sand bodies for these six major environments. The problems of sand-body predictions are also briefly summarized. Generally, three types of information are required: depositional environment, regional distribution of sand facies, and paleoslope. Usually prior experience with sandstone bodies of the same facies, preferably in the same basin, is very helpful. Locating a new sandstone body in a basin is usually much more difficult than drilling the first step-out well.