Interpretation of recent seismic and well data in the Gillis-English Bayou-West Manchester area of Calcasieu Parish, Louisiana, supports a complex structural history involving allochthonous salt, erosion, and faulting.

Since its discovery in 1934, Gillis-English Bayou field has produced over 195 bcf of gas and 19 MMbbl from Oligocene and Miocene sands. Unlike the aerially small, shallow, piercement salt dome fields along trend, Gillis-English Bayou field covers approximately 18 sq mi-aerially the largest field in the parish. West Manchester field, approximately six miles south, has produced over 120 bcf of gas and 2 MMbbl from Oligocene lower Hackberry sands. The associated salt sheet underlies at least 30 sq mi at depths of 15,000-20,000 ft and can be indirectly related to hydrocarbon accumulation in the area.

Associated with this vertical and lateral movement of salt is a significant Vicksburg erosional event underlying West Manchester field. In this area of thick Vicksburg sediments, over 1700 ft of section has been eroded.

AAPG Search and Discovery Article #90989©1993 GCAGS and Gulf Coast SEPM 43rd Annual Meeting, Shreveport, Louisiana, October 20-22, 1993.