ABSTRACT

One of the richest oil and gas producing areas in the United States is a 200 mile wide and 850 mile long belt from the Central Kansas Uplift across Oklahoma, north and west Texas to the Central Basin Platform, Delaware-Basin into New Mexico. More than 90% of all oil and gas produced from Ordovician-Cambrian rocks has come from this area and from accumulations extending from the grassroots downward to depths in excess of 26,000 feet in environmentally thick complex Arbuckle-Ellenburger Carbonates.

This areas' Arbuckle potential is emerging in fields like West Mayfield and Mills Ranch with producing wells averaging 15 million cubic feet of gas per day and gas reserves in excess of 20 Billion CFG per well.

Data from these fields plus other new wells drilled in the Oklahoma Arbuckle section measuring over 8000 feet in its hydrogen sulphide rich limestone depo-center and 5000 foot thick platform dolomites is revealing field examples and environmental models for deposition during Arbuckle time which localizes dolomite porosity and production occurrences in a predominate limestone environment with evaporites related to the entrapment.

The role Pre-Arbuckle Topography and Basement Volcanics played in the Arbuckle Environment and its structural evolution is important for several reasons. It was a rich organic foothold and the thick vertical and lateral volcanic lava flows on the sea bottom provided the sites for deposition of shallow water porous dolomites which were eventually to become the refuge for hydrocarbon entrapment in the Arbuckle.

The lithologic study summarizes regional concepts of limestone and dolomite distribution and stratigraphic relations of Cambrian and Ordovician strate which reveal some "Unique Dolomite" occurrences with oil and gas entrapped.