Dynamic Modeling of CO2 Geological Storage in the Arbuckle Saline Aquifer

Yevhen Holubnyak, Tiraz Birdie, Lynn Watney, Jason Rush, John Doveton, and Mina Fazel Alavi

The Arbuckle Group saline aquifer is a thick (>800 ft) and deeply buried (>3,500 ft) siliceous dolomite with interbedded shales. This aquifer is identified as an excellent candidate for geological CO2 storage due to its location and proximity to major CO2 emission sources, high storage capacity potential, and multiple overlying sealing units, which can ensure safe CO2 storage for the long term. A DOE sponsored pilot-scale project has been funded in which 40,000 metric tons of CO2 will be injected in the lower part of the Arbuckle reservoir over a period of 9 months at Wellington field in Sumner County, KS. The key objective of this work is to estimate the resulting rise in pore fluid pressure, the extent of CO2 plume migration, and geochemical stability of the formation rock and any structural features that may be present in order to insure that the CO2 injection will not compromise the underground sources of drinking water in the area. Another objective of this work is to estimate the potential storage CO2 capacity at the Wellington field and to suggest optimal injection strategy at this location. A detailed geocellular model of the Arbuckle reservoir was produced based on the existing well-logs, seismic data, drill stem tests, step rate test, and core analysis. The data from this model was upscaled to the CMG-based dual-permeability compositional model. The simulation results indicate that if the proposed injection scenario is implemented the injection pressure within the Arbuckle reservoir will not exceed the 300 psi threshold limit which can cause the Arbuckle brine to migrate into the overlying freshwater aquifers via improperly abandoned wells or faults. The CO2 plume is projected to be primarily vertical; spreading less than 1200 feet laterally. For the commercial scale injection the 20 M metric tons of CO2 were injected into the Arbuckle reservoir via single vertical, single horizontal, and multiple well schemes. 

AAPG Search and Discovery Article #90176©AAPG Mid-Continent Meeting, Wichita, Kansas, October 12-15, 2013