Kansas Geological Survey, Open-file Report 91-52, p. 81-82
Kansas Geological Survey
The Upper Devonian Misener member of the Chattanooga Shale is one of the major producing zones at Zenith field, Stafford County, Kansas. This field has produced 23 million barrels of 41° API gravity oil since production began in 1937. Hydrocarbons are trapped stratigraphically on a broad south-southwestward-plunging anticlinal fold off the Central Kansas uplift. Historically, production from the Misener includes 9,100 acres. However, only 2,000 acres are currently productive and produce less than 150 barrels of oil per day. Enhanced oil recovery methods are being considered to improve this rate. Detailed definition of the reservoir architecture by study of sequence stratigraphy, sedimentology, and diagenesis is extremely important to successfully attaining this goal.
At Zenith field the Kaskaskia Sequence (Sloss, 1963) is represented by two depositional sequences (DS 1 and DS2; cf., Vail et al., 1977). The older sequence, DS 1, is composed of two submembers of the Misener member, the lower Misener sandstone and an overlying siliceous carbonate unit called the Misener limestone. These two submembers form the main Misener reservoir. DS2 is composed of the upper Misener sandstone and shales typical of the Chattanooga Shale. These latter submembers form minor reservoir and top seal.
The lower Misener sandstone of DS 1 was deposited as a transgressive systems tract during an initial marine flooding of the Tippecanoe unconformity surface. Thickest accumulation of the lower Misener sandstone is to the eastern side of Zenith field where accommodation space was greatest. The following highstand system tract produced a carbonate ramp responsible for deposition of the Misener limestone in which supratidal, intertidal, and open-marine carbonates developed generally west of the lower Misener sandstone. Within the Misener limestone, this eastward-dipping ramp is expressed as restricted mud-rich supratidal-intertidal limestones replaced by chert to the west and thicker open-marine lime grainstones and packstones along the ramp edge to the east. This relatively thick carbonate package is correlative to a thin discontinuous distal limestone that extends eastward off the ramp, capping the lower Misener sandstone. Chert replacement of the supratidal-intertidal lithofacies is very extensive and has produced a stratiform chert. This replacement has produced, as well, thin beds and nodules of chert in the open-marine lithofacies. A subsequent lowstand in sea level produced exposure along the western limit of the Misener carbonate ramp. This exposure and associated unconformity is expressed as brecciation associated with tripolitic weathering of the cherts and karstification, resulting in a highly porous lithology. The eastern extent of this unconformity surface is uncertain. The unconformity surface, as well as the entire upper surface of the Misener limestone forms the sequence boundary between DS 1 and DS2.
The upper Misener sandstone was deposited either during the lowstand associated with exposure of the Misener limestone, or during subsequent marine flooding; hence, it is unclear if it is a lowstand or transgressive system tract. Nonetheless, the upper Misener sandstone filled an accommodation space present to the east of the Misener carbonate ramp. The upper Misener sandstone appears to onlap onto the edge of the ramp in the northeastern part of the field. As relative sea-level rise continued, Chattanooga Shales overstepped upper Misener sandstone and Misener limestone to form a top seal.
Sloss, L. L., 1963, Sequences in the cratonic interior of North America: Geological Society of America, Bulletin, v. 74, p. 93-113
Vail, P. R., Mitchum, Jr., R. M., and Thompson, III, S., 1977, Seismic stratigraphy and global changes of sea level, part 4--Global cycles of relative changes in sea level; in, Seismic Stratigraphy--Applications to Hydrocarbon Exploration, C. E. Payton, ed.: American Assoc. of Petroleum Geologists, Memoir 26, p. 83-97
Figure 1--Hypothesized development of depositional sequences of the Devonian Misener carbonate ramp.
Kansas Geological Survey
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Web version created June 29, 2012. Original publication date 1991.