Reservoir Characterization and Enhanced Oil Recovery (EOR) Potential of an Incised-valley-fill Sandstone Reservoir: Pleasant Prairie oil field, Southwestern Kansas

P. J. Senior, Tony Walton, and Martin Dubois

An Upper Mississippian Chesterian Stage incised-valley-fill sandstone reservoir in the Pleasant Prairie oil field in Finney and Haskell counties, Kansas, is a mature waterflood that is a candidate for enhanced oil recovery efforts through either chemical flooding or CO2 injection. The oil productive portion of the valley fill in Kansas extends north to south for 80 kilometers, from the 6 km cut in the Pleasant Prairie field nearly to the Oklahoma–Kansas border. Depositional environments in the Chesterian incised-valley fill range from more marine-influenced estuarine settings in the southern parts, near the Kansas–Oklahoma border, to more dominantly fluvial in the northern end of the valley at the Pleasant Prairie field. Porosity and permeability are generally higher at Pleasant Prairie compared to more marine-influenced Chesterian reservoirs down dip. Pleasant Prairie cores display 4 fining-upward parasequences of conglomerate and sandstone. Conglomerates at the base of each parasequence are laterally continuous. Most of the clasts are fragments of limestone. Calcite cement in the conglomerate and calcite or silica cement in some sandstone intervals reduces permeability, forming barriers or baffles to fluid flow. The reservoir facies consists of laterally continuous beds of very fine- to fine-grained sandstone. While distinct finely laminated, cross-bedded, and apparently structureless sandstone lithofacies can be recognized in the two cores, these different types of sandstone cannot be separately identified based on well logs or core petrophysical data. Sandstone and conglomerate, however, can be clearly differentiated by log response and core data. Reservoir modeling with Schlumberger Petrel™ software indicates 12.1–14.6 mmbo of OOIP, of which over 4.4mmbo has been produced. 

AAPG Search and Discovery Article #90176©AAPG Mid-Continent Meeting, Wichita, Kansas, October 12-15, 2013