Extensive stratigraphic accumulations of oil and gas along the northern shelf of the Anadarko basin have been the visions of petroleum geologists for more than two decades; however, only recently have these visions become a reality. Prolific discoveries at Laverne, Southwest Stockholm, Woodward, and pools of the "Cherokee trend" have focused the attention of all exploration men to the stratigraphic trap possibilities of the northern shelf area.

Early exploration along the shelf area was derived from surface indications and geophysical study. Test wells were drilled without the aid of gas detectors and modern methods of surveying the bore hole. Consequently, many prolific gas reservoirs were penetrated with the drill without evaluation.

The remedy for this situation has come from the many advancements made in the field of research which has developed new evaluation tools for the geologist.

Numerous deep tests along the shelf area and in the basin proper have enabled the geologist to familiarize himself with the vast possibilities of stratigraphic traps in sediments throughout the Middle and Upper Paleozoics, from the Silurian-Devonian into early Permian.

Convergence due to truncation and onlap, and interruption in deposition of sands and "reef" type limestones provide most of the stratigraphic traps of the northern shelf area. Multiple traps of this nature in any area are not uncommon. Two wells in Laverne have as many as four prolific gas horizons, all stratigraphic, which will gross the operator approximately $4,000,000 per well. More than 50 per cent of the completions in this pool are dual.

The area has a great future, and the returns will be gratifying to those adept in delineating stratigraphic traps.

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