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System: Pennsylvanian

Permian Carbonate--Province Summary

This Permian Carbonate 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).

Permian Carbonate Stratigraphic Gas Play

by Mitchell E. Henry and Timothy C. Hester

This play extends throughout the province and consists of all Lower Permian, Wolfcampian Council Grove, and Chase Group strata, except those included in the Wichita Mountains Uplift Play. Drilling depths to the top of the Chase Group range from about 800 to about 4,850 ft. This play is the most significant hydrocarbon producer in the province. The play is dominated by the Panhandle-Hugoton gas field, the largest gas field in the United States. Panhandle-Hugoton has coalesced, through the years, from what were then considered individual gas discoveries in Texas, Kansas, and Oklahoma, into a single huge producing entity. Although this is considered a single field, there are some differences in its various parts. The part of Panhandle-Hugoton located in the Texas Panhandle has significant oil accumulations in addition to a huge gas accumulation. The oil and gas accumulations in the Texas Panhandle part are primarily structurally controlled, whereas gas in other parts of Panhandle-Hugoton is stratigraphically trapped; hydrodynamics plays a role in both areas (Pippin, 1970). In the Texas Panhandle, the oil is located downdip from the gas, held in that position by the balance between gas and hydrostatic pressure (Rogatz, 1935). The oil part of the accumulation, which is now considered a single field, has amalgamated from more than 40 individual oil fields, an outcome predicted by Rogatz in 1935. The enormity of the gas production, the interconnected fields, and a predominantly carbonate lithology, are the principal defining features of this play.

Reservoirs

Reservoir rocks of this play include arkosic washes, and limestone and dolomite units of the Lower Permian Council Grove and Chase Groups. Thickness ranges from about 500 ft on the shelf areas to more than 2,000 ft near the Wichita Mountains front. Data from nine reservoirs show porosity ranging from 12 to 16 percent, with a median of about 15 percent. However, a study by Cities Service Oil and Gas Corp. (Shirley, 1986) found that porosity and permeability are not as uniform as previously thought. Hugoton reservoirs do not produce well without fracture treatment (Oil and Gas Journal, 1984).

Source rocks

Likely sources for hydrocarbons in this play may be virtually any of the thermally mature source rocks previously discussed in this province. No conclusive evidence is found for the existence of Permian source rocks in the province, however, Campbell and others (1988) discuss several lines of evidence to support that possibility. High-quality thermally mature source rocks are abundant just north of the oil and gas accumulations in the Texas Panhandle, and some workers have speculated that hydrocarbons may have migrated from a normally pressured Texas oil and gas field that was breached (Shirley, 1986). Panhandle-Hugoton gas pressure is characteristically low, initially 482 pounds per square inch (psi), less than half that expected for a given depth. Rice and others (1989) have suggested long distance migration (as much as several hundred miles) for gas found in the Panhandle-Hugoton area. They proposed that the gas may have been derived from Pennsylvanian or older source rocks in the central basin during the mature stage of hydrocarbon generation. Oil, on the other hand, may have come from Simpson or Woodford shales (Burruss and Hatch, 1989), and may not have migrated such great distances. The hydrocarbon source for Panhandle-Hugoton is not positively known. It is possible that generation and migration could have occurred over a long period of time with hydrocarbons trapped in multiple stages. The existence of huge quantities of hydrocarbon in this play indicates favorable timing between generation, migration and, trap formation.

Traps

Trapping mechanisms for the oil accumulations in the Texas Panhandle are primarily structural, and are related to the anticline and smaller structural features formed by the buried Amarillo-Wichita Uplift (Rogatz, 1935). Gas in the Texas Panhandle is localized by the same anticlinal structures. Hydrodynamics also plays an important role in localizing both oil and gas in this play (Rogatz, 1935, 1939; Hubbert, 1967; Pippin 1970). In the Oklahoma and Kansas parts of the field, gas is trapped along the western side by porosity loss where reservoir rocks grade into tight red beds. The overall distribution of the gas is modified by subsurface water flow toward the east (Rogatz, 1935, 1939; Hubbert, 1967). Seals for this play are dolomite and anhydrite beds of the overlying Permian Wichita Formation (Pippin 1970).

Exploration status

Nearly 30,000 wells penetrated the Permian carbonates in this play. Because many are not reported, the actual number of wells is much larger, probably in excess of 96,000. The Panhandle-Hugoton field has an estimated ultimate recovery of about 83 TCFG. Production from major accumulations ranges in depth from about 1,400 to about 4,300 ft.

Resource potential

The future potential for new major hydrocarbon discoveries in this play is not expected to be great. Undiscovered accumulations are not expected west of the Panhandle-Hugoton field boundary because of the apparent lack of rocks of reservoir quality; to the east, reservoir rocks are generally water wet. The large number of wells in the play leave little unexplored area. Our view of the play recognizes the fact that known accumulations are underpressured, and therefore, some accumulations may exist in already extensively drilled areas and may have simply been overlooked (Campbell and others 1988). An important implication here is that a extensively drilled area is not always well explored. Although additional production from infill drilling may prove significant, this part of the resource is not considered undiscovered. Historical discoveries, and well completion and production data were used to evaluate this play.

Play Map

map showing fields in this play

References

Burruss, R.C., and Hatch, J.R., 1989, Geochemistry of oils and hydrocarbon source rocks, greater Anadarko basin--evidence for multiple sources of oils and long-distance oil migration, in Johnson, K.S., ed., Anadarko Basin Symposium, 1988: Oklahoma Geological Survey Circular 90, p. 53-64.

Campbell, J.A., Mankin, C.J., Schwarzkopf, A.B., and Raymer, J.G., 1988, Habitat of petroleum in Permian rocks of the Midcontinent region, in Morgan, W.A., and Babcock, J.A., eds., Permian rocks of the Midcontinent: Midcontinent Society of the Economic Paleontologists and Mineralogists Special Publication no. 1, p. 13-35.

Hubbert, M.K., 1967, Application of hydrodynamics to oil exploration, in Proceedings of the Seventh World Petroleum Congress, Mexico City, Mexico: v. 1B, p. 59-67.

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.

Rogatz, Henry, 1935, Geology of Texas Panhandle oil and gas field: American Association of Petroleum Geologists Bulletin, v. 19, no. 8, p. 1089-1109.

Rogatz, Henry, 1939, Geology of Texas Panhandle oil and gas field: American Association of Petroleum Geologists Bulletin, v. 23, no. 7, p. 983-1053.

Shirley, Kathy, 1986, Hugoton gas field gets new life: American Association of Petroleum Geologists Explorer, v. 7, no. 8, p. 10-11.


Kansas Geological Survey, Digital Petroleum Atlas
Updated May 28, 1998
Comments to webadmin@kgs.ku.edu
URL=http://www.kgs.ku.edu/DPA/frontEnd/Anadarko/Permian/provSum.html