Gas Exploration in the Northern Paradox Salt Basin
Houston, William S., Brent L. Miller, Terrilyn M. Olson
Tom Brown, Inc, Denver, CO
The Paradox Basin salt anticline province of Colorado and Utah has a dubious reputation. Although well known for the Mississippian Lisbon Field, historically small Permo-Penn discoveries (e.g. Andy’s Mesa and Hamilton Creek Fields) have not generated sustained interest in the region. Innovative field evaluations, geologic interpretations and technological advances, however, are redefining the potential of this largely under-explored basin.
Conventional wisdom dictates that gas accumulations are concentrated along narrow fairways structurally positioned against salt anticlines. In reality, structural and stratigraphic complexities result in vertically and laterally compartmentalized targets. Structural dips and the integrity of sealing faults have implications for hydrocarbon emplacement and trapping. Diagenetic elements and limited well control further complicates predictions of reservoir quality.
Integral to an exploration strategy is a detailed understanding of available analogs. Structural complexity and petrophysical challenges once constrained Andy’s Mesa Field to an estimated ultimate recovery (EUR) of 20 BCFG. Revised interpretations from modern logs, core data and 3D seismic, however, have resulted in a better understanding of stratigraphic and structural elements, diagenetic impediments and seismic attributes. The resulting optimization of reservoir targets, drilling procedures and completion techniques now places the EUR for this field in excess of 100 BCF.
With a detailed understanding of field analogs comes a framework for targeting repeatable play types. A basin-wide 2D seismic grid delineates favorable structural trends, while 3D seismic provides insights into relationships between stratigraphy and paleostructure. This integrated, multidisciplinary approach is developing an exploration framework to redefine old and discover new plays.