The Pennsylvanian Wapanucka Limestone and Spiro sandstone comprise a third-order genetic sequence containing sediments and surfaces that record marine shallowing and deepening during the final stages of passive-margin deposition and the onset of foreland basin development in the Arkoma Basin. Within the lower part of the genetic sequence, the Wapanucka Limestone is comprised of two fourth-order depositional cycles identified as a lower seaward-stepping marine carbonate cycle and an upper landward-stepping mixed carbonate and siliciclastic cycle comprised of a landward siliciclastic and a seaward carbonate facies tracts. The siliciclastic facies at the top of the Wapanucka Limestone are laterally linked tidal deposits that conformably overlie shelf carbonates in a landward direction. The Wapanucka Limestone is overlain by the time-transgressive sub-Spiro shale. It is marine shale interval coeval with the Wapanucka Limestone, and the Spiro sandstone shoreface cycles present the Kinta field area.

The lower Atokan unconformity is interpreted as a sequence boundary and overlies the sub-Spiro and Wapanucka facies tracts, truncating older strata in a basinward direction. This unconformity created incised valleys that cut into the Wapanucka shelf and represents the maximum base-level fall (minimum accommodation) of the third-order genetic sequence. This unconformity partitioned sediment across the older Wapanucka shelf-margin, depositing a Spiro shelf-margin (lowstand) south of the present-day Choctaw and Ti Valley faults in the Ouachita Mountains. The thickest Spiro sandstone section is deposited in the base-level rise (transgression) of the third-order genetic sequence and contains four fourth-order aggradational/progradational cycles composed of valley-fill fluvial, estuarine, and marine shoreface cycles that progressively onlap the lower Atokan unconformity to the north.

Wapanucka and Spiro sandstone facies develop reservoir quality in several areas and are productive in discovered fields across the basin. In each of the system’s tracts, fourth-order cycles show systematic variation in reservoir quality, thickness, connectivity, and compartmentalization related to their position within the third-order genetic sequence. Spiro sandstone reservoirs deposited in a long-term (third-order) base-level rise are thicker; contain little carbonate skeletal material and carbonate cement; have greater connectivity; and display different channel architecture between adjacent incised valleys. Spiro sandstone estuarine and marine successions that are time-equivalent valley-fill deposits also develop reservoir quality with different depositional geometries, continuity, compartmentalization, and thickness across the entire study area. The Wapanucka Limestone is a nonreservoir unit. The Wapanucka sandstone and sub-Spiro shale are genetically related to the Wapanucka Limestone.

The regional correlation of this genetic sequence demonstrates the temporal and spatial distribution of different-age Spiro sandstone reservoirs in the Arkoma Basin, the correlation of a sequence boundary, and the coeval volume of rock in the distal part of the basin. Time-stratigraphic correlation from detailed facies analyses identifies a new correlation of the Wapanucka Limestone and Spiro sandstone, creating a higher-resolution framework for prediction of reservoir presence, reservoir connectivity, and compartmentalization in developed fields, in addition to a new depositional model predicting untested exploration fairways.