Cemen, Ibrahim¹, Marline Collins¹, Steve Hadaway¹, Osman Kaldirim¹, Gultekin Kaya¹, Justin Evans¹, Kris McPhail¹
(1) Oklahoma State University, Stillwater, OK

ABSTRACT: Thrust Faulting in the Frontal Ouachitas and the Arkoma Basin in Southeastern Oklahoma: Implications for Gas Exploration

The Frontal Ouachitas fold and thrust belt contains several south-dipping imbricate thrust faults in the hanging wall of the Choctaw fault, the leading-edge thrust of the belt. The Choctaw is a high angle thrust fault at the surface. It loses its dip and becomes flat at depth for about 3 to 6 kms before joining the Woodford Detachment with a tectonic ramp. We have distinguished two flat detachment surfaces below the Frontal Ouachitas; the Choctaw and Woodford Detachments. The lower Atokan Spiro/Wapanucka formation is present between the two detachments. The Woodford Detachment makes a ramp and continues in the Morrowan Springer shale in the Arkoma Basin. The strain partitioning from frontal Ouachitas to the Arkoma Basin is accommodated primarily by a triangle zone and associated duplex structure. The triangle zone is flanked by the Choctaw fault to the south and the Carbon fault to the north. The duplex structure is located between Springer Detachment (the floor thrust) and the Lower Atokan Detachment (the roof thrust), which continues northward and displaces the Red Oak sandstone before reaching a shallower depth and forming the Carbon fault as a north dipping backthrust below the San Bois syncline through a zero-displacement point. To the east of the Wilburton field, the Carbon fault makes a lateral ramp to the east and becomes a blind backthrust. The Carbon fault loses its separation eastward and dies out in the Wister Lake area where the strain partitioning takes place through the duplex structure only. The lower Atokan Spiro/Wapanucka formation generally produces gas in the duplex structure when it is in a structural high in the horse structures where thrust faults may have created permeability barriers for gas accumulation. This suggests that thrust faults of the duplex structure may have provided sealing for gas accumulation in the footwall of the Choctaw fault.

AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.