skip to main content


Title: The low salinity effect at high temperatures

The mechanism(s) of low salinity water flooding (LSWF) must be better understood at high temperatures and pressures if the method is to be applied in high T/P kaolinite-bearing sandstone reservoirs. We measured contact angles between a sandstone and an oil (acid number, AN = 3.98 mg KOH/g, base number, BN = 1.3 mg KOH/g) from a reservoir in the Tarim Field in western China in the presence of various water chemistries. We examined the effect of aqueous ionic solutions (formation brine, 100X diluted formation brine, and softened water), temperature (60, 100 and 140 °C) and pressure (20, 30, 40, and 50 MPa) on the contact angle. We also measured the zeta potential of the oil/water and water/rock interfaces to calculate oil/brine/rock disjoining pressures. A surface complexation model was developed to interpret contact angle measurements and compared with DLVO theory predictions. Contact angles were greatest in formation water, followed by the softened water, and low salinity water at the same pressure and temperature. Contact angles increased slightly with temperature, whereas pressure had little effect. DLVO and surface complexation modelling predicted similar wettability trends and allow reasonably accurate interpretation of core-flood results. Water chemistry has a much larger impact on LSWF thanmore » reservoir temperature and pressure. As a result, low salinity water flooding should work in high temperature and high pressure kaolinite-bearing sandstone reservoirs.« less
 [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [3]
  1. Curtin Univ., Western Australia (Australia); Southwest Petroleum Univ., Sichuan (China)
  2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  3. Curtin Univ., Western Australia (Australia)
  4. PetroChina Tarim Oilfield Co., Xinjiang (China)
  5. Southwest Petroleum Univ., Sichuan (China)
Publication Date:
Report Number(s):
SAND-2017-2399J; SAND-2016-12558J
Journal ID: ISSN 0016-2361; 651460
Grant/Contract Number:
Accepted Manuscript
Journal Name:
Additional Journal Information:
Journal Volume: 200; Journal Issue: C; Journal ID: ISSN 0016-2361
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1415659; OSTI ID: 1432215