The effects of SO2 contamination, brine salinity, pressure, and temperature on dynamic contact angles and interfacial tension of supercritical CO2/brine/quartz systems

Abstract

The successful implementation of geologic CO 2 sequestration schemes in deep saline aquifers requires storage sites with minimum risk of CO 2 leakage through the caprock and maximum storage capacity in the reservoir rock. Some of the essential parameters that affect the effectiveness of a storage scheme are the density of CO 2 , the interfacial tension between CO 2rich and aqueous phases, and the wettability of reservoir rock and caprock in contact with these fluids at reservoir conditions [1]. In this study, densities, interfacial tensions, and dynamic contact angles of CO 2 /brine/quartz systems at high temperatures and pressures were simultaneously measured using the Axisymmetric Drop Shape Analysis with no-Apex (ADSA-NA) method. Measurements were performed at pressures (2000-4000 psig), temperatures (50-100 °C), and brine salinities (0.2 to 5 M) relevant to carbon sequestration in deep saline aquifers. These experimental conditions had not been investigated in the past. Additionally, the effect of SO 2 as a co-contaminant (0-6 wt.%) was investigated on these parameters for the first time. Contact angle hysteresis was also examined and the possible implications of the results on different CO 2 trapping mechanisms were discussed.

A statistical analysis of the effects of pressure, temperature and salinity on contact angles in CO 2 –brine–quartz systems

“…(1) Data that we transcribed from published tables (Experiments 10-12 in Table 1 of Broseta et al, 2012; Table 2 of Saraji et al, 2013 and Table 1 of Saraji et al, 2014).…”

“…Despite being a potential source of "spurious effects on measurements" (Farokhpoor et al, 2013a) that warrants "a thorough surface preparation" , surface roughness is often unreported in published accounts of contact angle measurements. Only five of the studies examined in our analysis (Jung and Wan, 2012;Saraji et al, 2013Saraji et al, , 2014Wang et al, 2013;Sarmadivaleh et al, 2015) reported the roughness of the surfaces tested and surface roughness was therefore not included in our models. We note, however, that the inclusion of the study as a random effect will accommodate some of the between-study variability associated with unmeasured laboratory parameters such as surface roughness.…”

“…Contact-angle direction (stationary, water-advancing, waterreceding) is likely to be pertinent, both because there is some evidence that contact angles are higher for water-receding conditions (Broseta et al, 2012;Saraji et al, 2013Saraji et al, , 2014 and also because geosequestration mechanisms such as capillary trapping are influenced by directional contact-angle hysteresis (Pentland et al, 2011). Contact-angle direction was not included in our models, however, because although all studies reported their contact-angle directions only a few (Bikkina, 2011;Broseta et al, 2012;Saraji et al, 2013Saraji et al, , 2014 provided observations for multiple directions (and none combined stationary, or equilibrium, observations with either advancing or receding measurements).…”

“…Contact-angle direction was not included in our models, however, because although all studies reported their contact-angle directions only a few (Bikkina, 2011;Broseta et al, 2012;Saraji et al, 2013Saraji et al, , 2014 provided observations for multiple directions (and none combined stationary, or equilibrium, observations with either advancing or receding measurements). Without sufficient coverage both within and between studies the regression models will not yield a useful estimate for the effect of contact-angle direction (that is, in the absence of sufficient individual studies exploring the effect of direction the results of pooled analyses will mirror the results of the limited individual studies that explore multiple directions).…”

“…These discrepancies are generally attributed to study-specific factors including surface contamination or the surface roughness of the quartz substrates Iglauer et al, 2014), repeated surface exposure (Bikkina, 2011), contact-angle direction (that is, stationary, advancing or receding; see, for example, Saraji et al, 2013Saraji et al, , 2014, droplet size (Mills et al, 2011), subtle differences in surface materials including the type of quartz used (Dickson et al, 2006;Mills et al, 2011;Sarmadivaleh et al, 2015) but not measurement methods such as sessile drop versus captive bubble (Fig. 2;Montes Ruiz-Cabello et al, 2011).…”