Author Description

The first study phase presents a science-based methodology for quantifying risk profiles at GCS sites as part of the US Department of Energy's National Risk Assessment Partnership. The NRAP Integrated Assessment Model-Carbon Storage is implemented to a field scale project in a fractured saline aquifer located at Kevin Dome, Montana. Using NRAP-IAM-CS, the first phase finds that the potential amount of CO2 leakage is most sensitive to values of the target reservoir fracture permeability, fracture and matrix end-point CO2 relative permeability, hysteresis of CO2 relative permeability, capillary pressure, and permeability of confining rocks. Moreover, results estimate very low risk of CO2 leakage to the atmosphere unless the quality of the legacy well completions is extremely poor. In the second phase, an investigation of formation damage due to acidization and brine injection tests into the Middle Duperow Formation. The findings of the second phase of this study include: (1) well test analytical models indicate a positive total skin factor, i.e., permeability decline at the brine injection well, thus contradicting results of a previous study; (2) there are two possible scenarios that could lead to the interpreted positive total effective skin factor: partial penetration of the injection well screen and formation damage; (3) by matching the pressure buildup observed during three brine injection tests, numerical simulation results support the formation damage hypothesis; and (4) the formation damage could be explained by mechanical and chemical processes during brine injection that could clog the matrix/fracture system, for example, anhydrite fines migration and/or calcite precipitation.