ABSTRACT

Despite an agressive exploration effort by the Texas Company in the 1940's, the Apache Townsite Field escaped detection for four decades because the Bromide (Ordovician) sands were wet and the deeper formations were either not drilled or not properly evaluated. The discovery well of record produced a small amount of oil from a shallow Permian stratigraphic trap in 1972; the de facto discovery well was discovered by Core Petroleum, Ltd. in 1982 and completed as a gas well in the uppermost Arbuckle Group (Lower Ordovician). Additional drilling has confirmed the Arbuckle production and found oil and gas in the McLish Formation of the Simpson Group (Middle Ordovician).

This field occupies the crest of an asymmetrical anticline on an intermediate thrust fault block of the Wichita Mountain front; it is only one in a chain of several analogous, in-tandem structures which include the prolific Apache (Bromide Sand) Field just to the northwest. It can be shown that the Ordovician rocks which produce oil and gas at Apache Townsite have been vertically uplifted more than 20,000 ft (6100 m) and that the tectonic disturbance which created this chain of fields was the Arbuckle orogeny of Virgilian/Wolfcampian age. The source rocks for this field are presumed to be the structurally inferior Pennsylvanian and/or Late Mississippian shales. Those potential reservoir beds that were breached by pre-Pontotoc erosion have not been found to be economically productive.