Patterns of water, pressure, salinity, and chemical content within a basin can give much useful information for oil exploration. In the eastern Algerian Sahara a substantial increase in exploration efficiency has been achieved by combining regional hydrodynamic studies with classic geologic and geophysical studies.

This prolific area shows a wide variety of hydrodynamic phenomena. Two distinct areas, each with its own "style," are present.

(1) The northeast Sahara basin roughly coincides with the limit of Triassic salt occurrence and reservoir beds are sealed both vertically and laterally under abnormally high pressure. No flushing has taken place. The chemical characteristics of underground water are uniform within the basin.

(2) The southern Sahara basin coincides with the Illizi sedimentary basin. Slightly saline water moves hydrodynamically from the outcrop toward the central part of the basin. Hydrodynamic studies are of value here in defining the most prospective zone, in understanding the oil entrapment mechanism, and in facilitating correlations between different reservoirs.