Abstract

Reprocessing and application of tomography driven velocity modeling to vintage 2D seismic lines of the University of Texas Institute for Geophysics (UTIG) improves previous two-way time data into pre-stack depth-migrated Kirchoff and reverse time migration (RTM) stacks. The resulting depth images give better resolution of the depth and structure of stratigraphic sequences from the Perdido Fold Belt inside Alaminos Canyon, U.S., to the Bay of Campeche, Mexico. Salt provinces in both regions are characterized by large-scale decollement surfaces involved in downdip shortening, salt extrusion, and folding. Tying the reprocessed UTIG’s line into ION’s mega-regional GulfSPAN™ dataset provides an interpretational context to extend calibrated stratigraphic horizons across the entire western part of the Gulf of Mexico. An analogous crustal model of the Florida Shelf and Campeche Escarpment is adopted from previous studies and is applied to the ‘step up’ detachment surface at the continental-oceanic crust boundary beneath the salt in the Campeche area. Basement was apparently formed by Late Jurassic seafloor spreading and is uplifted into a broad flexural arch in the basin center, and Louann salt toes out inside Mexican waters in the southern Perdido Fold Belt. Upper Jurassic source rocks are believed to overlie most of the basement structure and mother salt. The abyssal plain displays evidence of voluminous sedimentation related to Laramide uplift and erosion, as well as paleocanyon incision, creating potential for deposition of reservoir-quality sandstone sourced from the Sierra Madre Oriental (northwestern Gulf of Mexico) and Sierra de Chiapas (southern Gulf of Mexico). The formation and charging of hydrocarbon reservoirs is documented in a series of geographically categorized “play concepts,” illustrated in the depth-migrated UTIG line.