Capillarity and wetting of carbon dioxide and brine during drainage in Berea sandstone at reservoir conditions

Abstract

The wettability of CO 2 -brine-rock systems will have a major impact on the management of carbon sequestration in subsurface geological formations. Recent contact angle measurement studies have reported sensitivity in wetting behavior of this system to pressure, temperature, and brine salinity. We report observations of the impact of reservoir conditions on the capillary pressure characteristic curve and relative permeability of a single Berea sandstone during drainage-CO 2 displacing brine-through effects on the wetting state. Eight reservoir condition drainage capillary pressure characteristic curves were measured using CO 2 and brine in a single fired Berea sandstone at pressures (5-20 MPa), temperatures (25-508C), and ionic strengths (0-5 mol kg 21 NaCl). A ninth measurement using a N 2 -water system provided a benchmark for capillarity with a strongly water wet system. The capillary pressure curves from each of the tests were found to be similar to the N 2 -water curve when scaled by the interfacial tension. Reservoir conditions were not found to have a significant impact on the capillary strength of the CO 2 -brine system during drainage through a variation in the wetting state. Two steady-state relative permeability measurements with CO 2 and brine and one with N 2 and brine similarly show little variation between conditions, consistent with the observation that the CO 2 -brine-sandstone system is water wetting and multiphase flow properties invariant across a wide range of reservoir conditions.

CO2 Wettability of Sandstones: Addressing Conflicting Capillary Behaviors

“…On the other hand, Pentland et al (), Pini et al (), and Pini and Benson () performed core‐flooding experiments on Berea sandstone rock cores that all showed predictable water‐wet capillary scaling behavior indicating no changes of the water‐wet conditions in the presence of scCO 2 . Recent work by Al‐Menhali et al () investigated the impact of pressure, temperature, and brine salinity on the capillarity and wetting properties of CO 2 and brine in Berea sandstone, and the authors observed that the wettability of the CO 2 ‐brine‐sandstone system was insensitive to reservoir conditions and that the system was strongly water wet and could be characterized by analog fluids. Evidence against wettability alteration is also shown by X‐ray fluorescence measurements of stable thick brine films on smooth and rough silica surfaces under reservoir scCO 2 conditions (Y. Kim et al, ).…”

Enhancement of CO2 trapping efficiency in heterogeneous reservoirs by water‐alternating gas injection

“…The effectiveness of the trapping mechanisms depends on various geological and hydraulic parameters, including geological reservoir heterogeneities, caprock properties, CO 2 ‐rock wettability, reservoir temperature, wettability heterogeneity, and brine salinity . Moreover, although many geological parameters cannot be changed for a particular site, it has been shown that intelligent selection of CO 2 injection technology (e.g.…”

“…These mechanisms include structural trapping (caprock barrier), 8,9 capillary trapping, [10][11][12][13][14][15][16] solubility trapping [17][18][19] and mineral trapping. [20][21][22][23][24][25] The effectiveness of the trapping mechanisms depends on various geological and hydraulic parameters, including geological reservoir heterogeneities, [26][27][28][29][30][31][32][33][34][35] caprock properties, 8,36 CO 2 -rock wettability, 26,[37][38][39][40][41][42][43] reservoir temperature, 44 wettability heterogeneity, 44 and brine salinity. 45,46 Moreover, although many geological parameters cannot be changed for a particular site, it has been shown that intelligent selection of CO 2 injection technology (e.g.…”

Wetting Behavior of Tight Rocks: From Core Scale to Pore Scale

“…Wettability is the tendency of a fluid to preferentially wet a solid surface in the presence of other fluid(s) (Anderson, 1986a;Donaldson & Alam, 2008a). Understanding the wettability of natural rocks has significant applications in petroleum reservoir engineering (Bultreys, Van Hoorebeke, et al, 2016;Kallel et al, 2016;Suicmez et al, 2008), cleanup of underground reservoirs contaminated by nonaqueous phase liquids (Al-Futaisi & Patzek, 2004;Essaid et al, 2015), and CO 2 sequestration in subsurface geological formations (Al-Menhali et al, 2015;Chaudhary et al, 2013Chaudhary et al, , 2015Iglauer et al, 2015). Wettability impacts (a) fluids distribution at the pore scale, (b) irreducible water saturation, (c) efficiency of an immiscible displacement such as water flooding in hydrocarbon reservoirs, (d) rock-fluid properties such as capillary pressure and relative permeability, and (e) electrical properties of porous media (Peters, 2012).…”