Effect of Temperature on Wettability of Oil/Brine/Rock Systems

Abstract

We report results from a systematic investigation of the effect of the temperature on the wettability of oil/brine/rock systems. An oil sample, produced from a sandstone reservoir, was tested on sandstone-like substrates (i.e., mica and quartz) in NaCl and MgCl2 solutions with concentrations ranging from 0 to 3 M. Raising the temperature from 25 to 50 °C has no discernible effect on the contact angle, regardless of substrate type, brine type, or salt concentration. Another oil sample, obtained from a carbonate reservoir, was examined on carbonate-like substrates (i.e., calcite) in NaCl and MgCl2 solutions over a concentration range of 0–1 M. The contact angles decrease as the temperature increases from 25 to 65 °C, and this temperature effect also strongly depends upon the brine type and salt concentration. A systematic examination of the ζ potential of rock/brine and oil/brine interfaces under different conditions and subsequent discussions indicate that contact angle and ζ potential may not be directly linked. These findings regarding the wettability of oil/brine/rock systems may improve the understanding of low-salinity wateflooding mechanisms by elucidating the combined effects of the temperature and other critical variables, including brine type, brine concentration, crude oil composition, and substrate type.

Wettability Alteration and Enhanced Oil Recovery Induced by Proximal Adsorption of Na+ , Cl− , Liu1, Wani2, Alhassan3 et al. 2018Phys. Rev. Applied515270View full textAdd to dashboardCite

“…1c. This result manifests the low-salinity effect that is observed in many experiments [14][15][16]18,19], and is in line with a recent contact angle measurement [18] (more oil-wet by 50° upon wetted by 1.0 M NaCl brine). It is worth noting that, in experiments, non-monotonicity of the dependence of contact angle on NaCl concentration was found [18], i.e.…”

“…The positive impact of temperature (the carbonate reservoir becomes more water-wet with increasing the temperature) has been reported in experiments [10,12,14]. For potential determining ions, it was attributed to the more pronounced surface charge alteration, as ion adsorption was enhanced by increasing the temperature 5,7 .…”

“…Surface wettability impacts a variety of issues that pertain to applications [1][2][3][4]. One of the major challenges in the oil industry is the enhancement of oil recovery (EOR) by water flooding in carbonate reservoirs [5][6][7][8][9][10][11][12][13][14][15][16][17]. Injection of smart water (water with optimized composition and salinity) is an efficient way of achieving EOR and wettability alteration has been proposed to be the driving mechanism [6].…”

“…It was found by zeta-potential measurements that Ca 2+ , Mg 2+ and SO 4 2-are strong potential-determining ions (ions that are strongly related to the surface charge/potential), while SO 4 2must act together with either Ca 2+ or Mg 2+ in order to improve the oil recovery [9][10][11][12][13]. Raising the temperature has been found to be of great benefit for EOR [12,14], while at high temperatures Mg 2+ can even substitute Ca 2+ from the chalk surface [12]. More recently, the injection of low-salinity brine in carbonate reservoirs was reported to enhance oil recovery [14][15][16][18][19][20].…”

“…Raising the temperature has been found to be of great benefit for EOR [12,14], while at high temperatures Mg 2+ can even substitute Ca 2+ from the chalk surface [12]. More recently, the injection of low-salinity brine in carbonate reservoirs was reported to enhance oil recovery [14][15][16][18][19][20]. It was further demonstrated that the low-salinity effect results from wettability alteration rather than mineral dissolution [19,21], but the specific mechanism responsible for the wettability alteration remains largely unknown.…”