Upper Mississippian (Chester) Ooid Shoals: Austin Upper Mississippian Field New Mexico and Mocane-Laverne Field Oklahoma and their Relation to North American Chester Paleogeography
D. C. Hamilton1 and G. B. Asquith2
1Independent, Midland, Texas
2Texas Tech University, Lubbock, Texas
Upper Chester ooid grainstones produce gas in both the Austin Upper Mississippian Field in Lea County, New Mexico (13 BCF+130 MBO) and the Mocane-Laverne Field in Harper and Beaver counties, Oklahoma (703 BCF). These ooid grainstones were deposited in an upper Chester HST due to a loss of accommodation space. The reservoirs in both fields are skeletal ooid grainstones with intergranular porosity.
The ooid grainstones in southeast New Mexico were deposited as a series of northeast-southwest trending elongate ooid shoals perpendicular to the Chester shelf margin. In the Mocane-Laverne Field in northwest Oklahoma the Chester ooid shoals exhibit a similar geometry, but are oriented northwest-southeast also perpendicular to the Chester shelf margin. The orientation of the Chester ooid shoals perpendicular to the shelf margin is similar to the orientation of modern ooid tidal bar belts at the end of the Tongue of the Ocean in the Bahamas. Chester ooid grainstones have also been reported in southwest New Mexico, West Texas, north-central Texas, southwest Kansas and north-central Arkansas plus the Illinois and Appalachian basins. Therefore, south of the Mississippian paleoequator Chester ooid shoals may have extended across southern New Mexico around the Texas Peninsula into Oklahoma across to Arkansas all the way to the Appalachian Basin; deposited along the upper Mississippian shelf margin a distance of over 2,600 miles.
AAPG Search and Discovery Article #90905©2001 AAPG Southwest Section Meeting, Dallas, Texas