Assessment of the CO2 sealing efficiency of pelitic rocksTwo-phase flow and diffusive transport

Mathematical modeling of the long-term safety of carbon dioxide (CO2) storage in underground reservoirs

“…Formation of solid carbonates is the most permanenent and desirable form of CO 2 storage, but is a slow process at ambient temperature conditions. There is considerable uncertainty about rock-fluid reaction rates applicable to field-scale systems, but it is likely that hundreds of years or more would be required for significant reaction process 9.3.3 Leakage along faults, fracture zones, and wellbores storage reservoirs and operations for Co 2 will be selected and designed in such a way that intact caprock overlying a CO 2 storage reservoir will adequately contain Co 2 , due to sufficiently large entry pressure for nonwetting phase and/or sufficiently small permeability (Krooss et al, 2005;Bachu and Bennion, 2007;Chiquet et al, 2007a,b). Concerns about longterm storage integrity arise from potential caprock imperfections that may provide preferential pathways for upward gas migration, such as fracture zones and faults, or improperly abandoned wells.…”

“…At typical subsurface conditions for terrestrial Co 2 storage projects, the in situ density of the gas phase will be less than the density of the aqueous phase, generating a buoyancy force that will drive CO 2 towards the top of the permeable interval. Co 2 storage would be made into formations that have a suitable caprock of low permeability to contain the CO 2 , and injection pressures would be limited so as not to exceed the capillary entry pressure of the caprock (Krooss et al, 2005;Bachu and Bennion, 2007;Chiquet © Woodhead Publishing Limited, 2010et al, 2007bGibson-Poole et al, 2008). However, as CO 2 spreads beneath the caprock, containment could be compromised if (sub-)vertical permeable pathways with low or vanishing entry pressures were encountered, such as fracture zones and faults, or improperly abandoned wells.…”

Capillary Entry Pressure of Oil-based Muds in Shales: The Key to the Success of Oil-based Muds

“…While much effort has been dedicated to the evaluation of reservoir rock properties using capillary pressure data, not much has been done to evaluate the impact of capillary entry pressure on shale stability. Krooss et al (2004) employed a pressure transmission test to measure capillary entry pressures in shale and mud rocks using CO 2 , N 2 , and NH 4 as the non-wetting fluids. In their study, gas breakthrough experiments were performed by creating an instantaneous high pressure gradient (up to 20 MPa) across the shale sample and monitoring the gas flux across the shale by means of a closed pressure chamber downstream of the shale.…”

Estimating the Reservoir Hydrocarbon Capacity Through Measurement of the Minimum Capillary Entry Pressure of Shale Cap-Rocks

“…Krooss et al (2004) employed a pressure transmission test to measure capillary entry pressures in shale and mud rocks using CO 2 , N 2 and NH 4 as the non-wetting fluids. While many papers are dedicated to the evaluation of reservoir rock properties using capillary pressure data, not much work has been done on capillary pressures for shales.…”