Case treatments are presented or pointed to in the literature which include examples of prospecting by refraction fans, a geoelectrical method (Eltran), and chemical analyses of soils, soil gases, and ground waters.

These type geophysical and geochemical anomalies are associated with producing structure, which, in several cases, display only low relief at considerable depths, where the anomalous data represent modifications of shallow sediments undeformed by the underlying structure.

These illustrations indicate that the column of sediments over a petroleum accumulation displays properties which differ from those of the adjacent sediments of the same geological age. As a result of these differences in properties, observed even where no observable structural deformation has taken place in the affected sediments, a dynamic rather than a static conception of a petroleum accumulation is indicated. A description and a discussion follow of a working hypothesis which has been proposed to account for these geochemical manifestations of a petroleum accumulation.

Geochemical prospecting takes for its objectives the recognition of the geochemical manifestations of a petroleum accumulation, and their interpretation in terms of their origin, of the petroleum accumulation itself, by means of the local and regional geology.