Print this pageAbstract: Oil and Gas Possibilities, Redwall Limestone, Black Mesa Basin, Arizona
The Redwall Limestone, covering an area of 50,000 sq mi (129,499 sq km) in northeastern Arizona, was analyzed texturally to determine facies relations and environments of deposition. In the study area the Redwall crops out only in the Grand Canyon and along the Mogollon Rim; therefore, most of the data were obtained from the analysis of samples from 32 wells. The underlying Devonian(?) Ouray Limestone was included in the study because it is related depositionally. The Redwall in the study area is overlain by the Pennsylvanian Molas Formation.
Carbonate grain types were classified into the following textures: dolomite, stromatolitic wackestone, pisolitic packstone, calcispheric packstone, pelletal packstone, oolitic packstone and grainstone, foraminiferal grainstone, crinoidal packstone and grainstone. The textures were grouped into four depositional environmental units: supratidal; dolomite and stromatolitic wackestone, protected "intratidal;" pelletal packestone and oolitic grainstone, open "intratidal;" pelletal packstone and oolitic grainstone, open marine; crinoidal packstone.
Limited oil and gas production in the Redwall has been confined to the extreme northeastern part of Arizona along the south edge of the Paradox basin. No commercial production has been discovered in the Black Mesa basin. Porosity in the Redwall consists of two basic types: (1) primary intergranular type present in the oolitic grainstone and crinoidal grainstone facies, and (2) secondary type formed by dolomitization or dissolution of crinoid columnals. Faulted structural traps appear to be the most promising for exploration.
AAPG Search and Discovery Article #90971©1976 AAPG-SEPM Rocky Mountain Sections 25th Annual Meeting, Billings, Montana