Exceptional Marine Sand Bodies in the Paleozoic of Oklahoma

FRITZ, RICHARD D., MASERA Corporation, Tulsa, OK

Of the wide variety of sandstone reservoirs in Oklahoma, the most unusual types of sand bodies are present in the Atokan Spiro Sandstone, Devonian Misener Sandstone, and Morrowan lower Morrow Sandstone. The common factors of these sand bodies are that, upon correlation and mapping, these units are channel-like (fluvial-deltaic) in geometry, but from petrographic evidence they are quartz-rich shallow-marine units with the exclusion of intraclastic and diagenetic constituents.

Stratigraphic mapping of the Spiro Sandstone of the Arkoma basin indicates two types of sand bodies: channel and sheet. The marine channel-like deposits, 10-150 ft thick, probably were deposited on a paleosurface produced by a pre-Atokan unconformity. Examination of cores and outcrops indicate that both the channel and sheet Spiro sandstones contain shallow-marine fossils, limestones, peloidal chamosite, burrows, and bioturbation, all indicative of a shallow-marine setting.

The Misener Sandstone of north-central Oklahoma ranges from 10-100 ft thick with sharp boundaries. The sandstone deposited in pre-Frisco/Woodford eroded paleochannels. Core evidence for shallow-marine deposition is glauconite, phospatic fossils and clasts, burrows, and bioturbation. These rocks probably were deposited in an embayed, estuary-like environment.

The lower Morrow Sandstone of the Anadarko basin is similar in geometry, except that the sand bodies are multistoried and multilateral and do not appear to be associated with a regional unconformity. The lower Morrow sandstones, usually 30-60 ft thick, commonly are elongated and deposited parallel to the shoreline. Deposition is inferred to be shallow marine from marine fossils and glauconite.

AAPG Search and Discovery Article #91011©1991 AAPG Southwest Section Meeting, Abilene, Texas, February 9-12, 1991 (2009)