Sunday, August 9, 2009

Pressure build-up during CO2 storage in partially confined aquifers

YagnaDeepika Orugantia and Steven L. Bryant

"As the number or proximity of faults increases, the injectivity decreases slightly. In contrast to injectivity, contours of elevated pressures are sensitive to faults. They extend farther as the number or proximity of faults increases, increasing the area of influence and thus the risk of failure (seal fracture, fault activation) significantly. Thus well placement relative to known faults is an important design consideration. The effect of aquifer depth on pressure build-up due to injection is also investigated. The variation of fluid viscosity with pressure and temperature (brine viscosity is much more sensitive than CO2 viscosity) is the dominant effect on injectivity and pressure build-up. An important overall message is that contours of elevated pressure extend much farther into the aquifer than the CO2 plume itself. Thus risk assessment that focuses exclusively on CO2 may underestimate actual project risk."

The link to this abstract is here