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Play Start Page Play Summary Resources Kansas Info Region: Northern Midcontinent
System: Pennsylvanian

Upper Virgilian--Province Summary

This Upper Virgilian Play information is from the U. S. Geological Survey 1995 National Assessment of United States Oil and Gas Resources (available on CD-ROM from the U.S.G.S. as Digital Data Series DDS-30, Release 2).

Upper Virgillian Stratigraphic Oil and Gas Play

by Mitchell E. Henry and Timothy C. Hester

This play extends throughout the province, except in the southwest part of the Texas Panhandle and on the Wichita Mountains front where Upper Virgilian strata are absent. Strata consists of all Middle and Upper Virgilian Shawnee, Wabaunsee, and Admire Group rocks, including correlative units in the Ada Group and in the lower part of the Ponotoc Group. Drilling depths to the top of rocks in this play range from about 2,000 ft in the east-central part to about 9,000 ft in the deep southern part. The principal defining features of this play are that both oil and gas are produced, primarily from limestone reservoirs.


Reservoir rocks are generally limestones of the Shawnee, Wabaunsee, and Admire Groups. Most of these rocks are oolitic and skeletal grainstones, originally formed in high- energy environments, in which subsequent leaching resulted in secondary porosity development (Parham, 1993). Reported porosity values range from 8 to 17 percent, with a median value of 13 percent. Because most porosity is secondary, porosity in yet undiscovered reservoirs is expected to be good but highly variable.

Source rocks and timing

Source rocks for this play are unknown, but the general lack of thermally mature rocks in the immediate producing areas suggests that longer distance migration of hydrocarbons may be involved (Rice and others, 1989). Quality of possible source rocks for this play has been discussed in other Pennsylvanian plays such as in the Morrow Sandstone Gas and Oil Stratigraphic or Atokan Sandstone Stratigraphic Gas plays. Strata in this play generally thicken southward from about 400 to about 3,500 ft. The presence of major accumulations indicates that the timing of hydrocarbon generation and migration, and trap formation is favorable for the charging of reservoirs in this play.


The most common trap type in this play is stratigraphic, although structural and combination types do exist. Stratigraphic traps are probably formed by overlying shales. Hydrodynamic trapping is an important mechanism at the Greenwood gas area (Pippin, 1985). Known accumulations occur at depths of about 3,000 to 6,100 ft with a median depth of about 4,000 ft.

Exploration status

This play is extensively explored. Almost 16,000 wells have been reported to reach rocks of this play. The large number of wells targeting Chesterian through Lower Virgilian rocks could bring that total to about 79,000. Seventeen major accumulations are assigned to this play; 13 gas and 4 oil. The largest gas accumulation is at Greenwood gas area, with an estimated ultimate recovery of 1.8 TCFG. The largest oil accumulation is at Quinduno north field, with an estimated ultimate recovery of 13 MMBO.

Resource potential

The potential for future major hydrocarbon discoveries in this play is projected to be insignificant, primarily because of the relatively few major accumulations contained in a very intensely explored area. Because of the evidence of long distance migration of thermally generated gas, the lack of thermally mature source rocks is not a serious liability for this play. Historical discovery and well completion data were the major sources of information used for assessment of this play.

Play Map

map showing fields in this play


Pippin, Lloyd, 1970, Panhandle-Hugoton field, Texas-Oklahoma-Kansas--the first fifty years, in Halbouty, M.T., ed., Geology of giant petroleum fields: American Association of Petroleum Geologists Memoir 14, p. 204-222.

Rice, D.D., Threlkeld, C.N., and Vuletich, A.K., 1989, Characterization and origin of natural gasses of the Anadarko basin, in Johnson, K.S., ed., Anadarko Basin Symposium, 1988: Oklahoma Geological Survey Circular 90, p. 47-52.

Kansas Geological Survey, Digital Petroleum Atlas
Updated May 28, 1998
Comments to webadmin@kgs.ku.edu