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 ...