About This Item

Share This Item

The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 42 (1958)

Issue: 1. (January)

First Page: 210

Last Page: 210

Title: Differential Entrapment of Oil and Gas in Arbuckle Dolomite in Central Kansas: ABSTRACT

Author(s): Robert F. Walters

Article Type: Meeting abstract

Abstract:

In central Kansas thousands of wells produce oil from the Arbuckle dolomite of Cambro-Ordovician age at depths from 3,200 to 4,400 feet. A few hundred wells produce gas. Reservoir porosity consists of intergranular space between dolomite rhombs, of irregular pin-point to cavernous voids, and of vertical fractures. This porosity was formed, or improved, by solution in early Pennsylvanian time when the dolomite beds cropped out on a low relief land surface. Ground water moved downward through joints, then laterally along bedding planes in the soluble dolomite, continuing down dip under Ordovician Simpson shale cover on the flanks of the Central Kansas uplift. The gently tilted, truncated, solution-riddled, porous, and permeable Arbuckle beds were buried under Pennsylvanian hales and limestones which provide an impervious seal. Oil and gas are trapped at the top of the Arbuckle on structural highs, whether anticlinal folds, buried hills, or traps formed by barriers such as clay-filled solution valleys. Dips are half of one degree or less.

The lowest Arbuckle traps such as the Shady and Zook fields of Pawnee County produce sour gas from depths near 2,000 feet below sea-level. In the Sweeney, Ash Creek, and Pawnee Rock fields of Pawnee County gas is produced from the Arbuckle near 1,800, 1,750, and 1,650 feet subsea, respectively, with a thin oil column present in each field. Both oil and gas are produced from the Otis-Albert field of Rush and Barton counties where the gas-oil contact is 1,600 feet subsea. Oil, and only oil, is trapped in the major Arbuckle fields of Rice, Barton, Russell, Ellis, Rooks and Graham counties at subsea depths of 1,600-1,400 feet. In the Kraft-Prusa field of Barton County the oil-water contact is 1,465 feet subsea. The critical closure of the Arbuckle anticline is also 1,465 feet, indicating hat the reservoir is exactly filled with oil. In Ellsworth County, a large anticline with porous Arbuckle as high as 1,350 feet subsea contains only salt water.

This pattern of differential entrapment of gas and oil accords closely with the theoretical distribution described by Gussow in his "Differential Entrapment Principle." It is concluded that oil and gas migrated out of the Anadarko basin of Oklahoma northward through the Arbuckle for several hundred miles due to regional tilting, and spilled upward under an impervious roof of Ordovician Simpson shale and Pennsylvanian shale until trapped in central Kansas. Time of tilting, hence migration, was post-Permian; important migration appears to have occurred in Cretaceous time.

End_of_Article - Last_Page 210------------

Copyright 1997 American Association of Petroleum Geologists