Documented Subsurface Three-Dimensional Geological Heterogeneity in the Weber/Tensleep Sandstones and Madison Carbonates: Wyoming’s Highest-Priority CO₂/Hydrocarbon Storage and Production Reservoirs

The greatest uncertainty in numerically simulating fluid-flow or fluid-storage processes in high-priority reservoir intervals is characterizing geological heterogeneity in three dimensions. In Wyoming, the reservoir intervals with the greatest potential for CO₂ and natural gas storage, CO₂/He production, and enhanced oil recovery are the Paleozoic Madison and Tensleep/Weber formations. To substantially reduce risk in modeling fluid-flow, fluid storage, and rock/fluid interactions in the Weber/Tensleep and Madison reservoirs, researchers involved with the Wyoming Carbon Underground Storage Project at the University of Wyoming’s Carbon Management Institute (part of the School of Energy Resources) have integrated 3-D seismic data with well log results and core observations to construct 10-square-mile porosity, permeability, lithofacies, and fracture distribution volumes. A 5 mile × 5 mile 3-D seismic survey and a 12,810-foot-deep stratigraphic test well (more than 910 feet of core and complete log suite retrieved) are the basis of the seismic interpretation. Within the volumes, we can now isolate individual reservoir horizons and construct maps of the distribution of seismic attributes and associated petrophysical properties. The three-dimensional distribution of heterogeneity in petrophysical properties of the reservoir intervals results from the seismic/log/core/geology integration. The 3-D seismic survey area and stratigraphic test well lie on the east flank of the Rock Springs Uplift, a 35 mile × 50 mile anticline with 4-way closure, 10,000 feet of structural relief, multiple outstanding confining layers above the reservoir intervals, and 8,000 feet of vertical separation from fresh water aquifers. The results from this project have significant utility in reducing risk in a diverse set of CO₂ storage/hydrocarbon production projects in the Rocky Mountain region. This work establishes a strategy for dealing with projects relating to deep (>10,000 feet) injection/storage and production of CO₂/hydrocarbons in deep saline aquifers - reservoirs generally considered too deep and/or too tight.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California