Structural characterization of the Emperor and Halley fields, Winkler County, West Texas

Abstract

The Halley and Emperor fields, Winkler County, West Texas, are located along the western margin of the Central Basin Platform (CBP), a late Paleozoic fault-bounded structural high in the Permian Basin. Well data, regional 2D seismic lines, and a 3D seismic data set were used to develop a detailed structural and stratigraphic interpretation for the area. Variance volume attributes were derived from the 3D seismic data, which improved imaging of subsurface features. The Halley and Emperor fields are situated over asymmetric anticlines with short steeper limbs that are faulted by steeply dipping reverse faults with a component of right-lateral strike-slip displacement. The orientation of the fold axes and faults is NNW-SSE, which is parallel to the overall trend of the CBP's western margin. Deformation occurred during late Mississippian to early Leonardian (Early Permian) time. The CBP can be subdivided into two major blocks or tectonic domains: the Andector Block to the north and the Fort Stockton Block to the south. These blocks were located between an inferred right-lateral mega-shear, which forced the Andector and Fort Stockton blocks to undergo clockwise rotation. A left-lateral shear zone must have existed along the E-W fault boundary between the Fort Stockton and Andector blocks, in order to accommodate clockwise rotation of the blocks. The Halley structure is situated at the southwestern corner of the Andector Block and shows evidence of younger middle Pennsylvanian to middle Leonardian left-lateral strike-slip deformation. In contrast, deformation along the Emperor structure to the north had ceased by late Pennsylvanian time, as indicated by the age of strata that onlap the structure and fault penetration patterns.