Reserves of ultimately recoverable oil and gas in the Mid-Continent (17.3 billion bbl and 130.0 trillion cu ft, respectively) are nearing depletion. Production through 1967 of 14.9 billion bbl of oil and 81.4 trillion cu ft of gas dictates this conclusion. A detailed review of Mid-Continent geology indicates that future potential oil and gas reserves of 1.7 billion bbl and 44.5 trillion cu ft, respectively, remain to be found. These figures represent the total of "probable," "possible," and "speculative" potential reserves as defined by the Potential Gas Committee.

The Texas Panhandle and Oklahoma should furnish 54 percent (932.0 million bbl) of the estimated new potential oil reserves; Kansas, 32 percent (561.3 million bbl); Nebraska, 12 percent (201.8 million bbl); and Missouri and Iowa, 2 percent (26.6 million bbl). The Pennsylvanian System is believed to contain the most important potential reservoirs--32.7 percent (563.0 million bbl) of the estimated new oil reserves--followed by the Middle and Upper Ordovician, 20.4 percent (352.3 million bbl); the Lower Devonian-Silurian, 16.7 percent (286.9 million bbl); the Mississippian, 13.8 percent (237.0 million bbl); the Cambrian-Lower Ordovician, 12.2 percent (210.0 million bbl); the Permian, 2.3 percent (39.0 million bbl); the Middle and Upper Devonian, 1.9 percent (32.5 million bbl); and the Cre aceous, about 0.5 percent (1.0 million bbl).

Old established producing areas should continue to furnish new potential reserves as a result of infill drilling and stepouts, but at a decreasing rate. Potential reserves attributed to reservoirs in southeast Kansas and northeast Oklahoma (Pennsylvanian, Mississippian, Middle Devonian, Silurian, Middle Ordovician, and Cambrian-Lower Ordovician) and southern Oklahoma (Cretaceous, Permian, Pennsylvanian, Mississippian, Lower Devonian-Silurian, Middle Ordovician, and Cambrian-Lower Ordovician) are optimistic estimates based on anticipated exploration activities.

The Cambridge arch in Nebraska, the northern shelf of the Anadarko basin, and the Hugoton embayment should furnish significant new potential reserves from Pennsylvanian rocks. The pre-Pennsylvanian section should become the most important future reservoir as exploration for structural traps continues in the deeper parts of the Anadarko and Ardmore basins, the Hugoton embayment, and the Salina and Forest City basins.

The Texas Panhandle and Oklahoma should furnish 75.3 percent (33,543 billion cu ft) of the estimated new potential gas reserves; northern Arkansas, 19.3 percent (8,600 billion cu ft); and Kansas, 5.4 percent (2,400 billion cu ft). The Lower Devonian-Silurian section is the most important future reservoir, containing 38.0 percent (16,900 billion cu ft) of the estimated new potential gas reserves. It is followed by the Pennsylvanian, 24.5 percent (10,900 billion cu ft); the Mississippian, 17.7 percent (7,900 billion cu ft); the Cambrian-Lower Ordovician, 10.8 percent (4,810 billion cu ft); the Middle Ordovician, 6.0 percent (2,685 billion cu ft); and the Permian, 3.0 percent (1,348 billion cu ft).

The deeper parts of both the Anadarko and Arkoma basins should furnish significant new reserves from

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Pennsylvanian and pre-Pennsylvanian strata. The Hugoton embayment should furnish new reserves from Permian, Pennsylvanian, and Mississippian rocks. Structural traps will be of primary importance, initially, in the deep Anadarko basin. Stratigraphic traps will be important in the Arkoma basin and the Hugoton embayment.