Two phase brine- CO2 flow experiments in synthetic and natural media

Industrial scale injection of anthropogenic carbon dioxide into the crustal lithosphere has been proposed to reduce atmospheric accumulation. Much of this injection is expected to occur in saline reservoirs. An understanding of two-phase brine- CO2 flow is necessary for predicting storage capacity, fluid migration, and injectivity in geologic reservoirs. Additionally, the chemical reactivity of the rock matrix with CO2(l) affects the transport properties of the rock. A flow system for measuring two-phase transport of CO2 and brine is presented in this paper. The system is capable of displacing brine with either liquid or supercritical CO2. Special effort was taken to circumvent capillary end-effects in these experiments. Drainage end point relative permeability of CO2 displacing brine is found to be in the range of 0.34–0.44, much lower than what is expected for a nonwetting fluid. Such low relative permeabilities would tend to decrease injectivity while increasing displacement efficiency