Integrated Reservoir Characterization of a Carbonate Ramp Reservoir, South Dagger Draw Field, New Mexico: Seismic Data Are Only Part of the Story

South Dagger Draw (SDD) field, located in southeast New Mexico, produces hydrocarbons from complex sigmoid-oblique clinoforms of the Pennsylvanian Canyon and Cisco Formations. South Dagger Draw field, a combination structural-stratigraphic trap, represents the northern extension of the Indian Basin field. Through February 2001, the Indian Basin and SDD fields together had produced nearly 23 million bbl of oil and 2 tcf of gas from Marathon Oil Company-held acreage. Vuggy porosity, formed dominantly in algal biostromes and bioherms located at the ramp-margin position of each clinoform, represents the primary reservoir. Vugs were formed by acidic hydrothermal fluids that migrated upward along joints and were baffled beneath shales, resulting in dissolution zones that are controlled by the interplay between structural joints and stratigraphic shales and carbonates. Data used in the study include logs, cores, modern wire-line log suites, borehole image logs, and three-dimensional (3-D) acoustic impedance values from inversion of seismic data. Seismic data provide interwell information helpful for determining the present-day structure of the field but not particularly useful for interpreting the stratigraphy. High-frequency sequence-stratigraphic interpretation, guided by a depositional model derived from description of cores and outcrops, was accomplished using a necessary combination of well logs, cores, and seismic data. The sequence-stratigraphic interpretation served as input for multiple iterative seismic inversions and provided the framework for the integrated 3-D geologic model.