Although a comparatively large number of wells have been drilled in eastern Arkansas, relatively little is known about the subsurface geology of the area. Many oil operators who have drilled wells in the past have failed to keep any sort of accurate record of the formations penetrated by their test holes. A study of some fifty-eight of the better well logs has, in a general sort of way, aided in evaluating the oil and gas possibilities of the area. In two wells an excellent record of the rocks drilled was obtained. They furnish key sections for future correlations (Plates II and III in pocket).

Oil and gas possibilities in Tertiary rocks are not good. Chances for commercial production in the Nacatoch are considered fairly promising. This sand is of sufficient thickness and porous enough to serve as a reservoir bed. Hovever, no appreciable shows of oil and gas have been encountered in the Nacatoch. At the base of the Cretaceous and overlying the Paleozoic floor occurs a basal sand. It has good possibilities as a future oil sand if found on structure or pinched out up the regional dip. Possibilities of Paleozoic production are unknown at the present time. Little is known about the character or subsurface distribution of the older rocks in eastern Arkansas. There also exists some possibility that intrusive igneous bodies, similar to the nepheline syenite plugs near Little Rock, may exist in the deeper portions of the Mississippi embayment. If so, oil traps may be associated with the igneous mass as flanking sands. They could possibly be formed by arching of the overlying sediments. Such structures either could be the result of tectonic forces or be due to compaction of the sediments surrounding the igneous body.

*Includes: 159 pages, 3 plates, 2 figures and 20 tables

Bulletin 14 (6.02 MB)

Plate 1 (3.48 MB)

Plate 2 (1.67 MB)

Plate 3 (2.3 MB)