Straightforward Assessment of Wettability Changes
by Washburn Capillary Rise: Toward a Screening Tool for Selecting
Water Compositions for Improved Oil Recovery
posted on 2024-02-03, 18:43authored byValérie Molinier, Laura Pauliet, Alexandra Klimenko, Nicolas Passade-Boupat, Maurice Bourrel
Evaluating the wettability
state of reservoir rocks is key for
understanding and optimizing waterflooding and improved oil recovery
techniques that imply the use of low-salinity water. Aside from established
petrophysical techniques, such as Amott imbibition tests, we evaluated
the Washburn capillary rise method as a low-cost, easy-to-implement,
and rapid screening tool for probing the wettability state of rock
samples. The well-known limitations of this method are discussed and
circumvented. We show that measuring the capillary rise of two liquids
brine and n-octaneis required to
assess the evolution of the wettability state of a material induced
by various treatments. The wettability state is quantified by the
adhesion tension of brine to the solid. The higher the adhesion tension
of brine, the more water-wet the sample. An increase in oil-wetness
is observed when the sample is contacted with a crude oil or its released
waters; an increase in water-wetness is obtained by postcontacting
the oil-wet sample with low-salinity brine or surfactant solutions.
The Washburn capillary rise is revealed to be a robust method for
screening wettability alteration. With a typical duration of 1–10
min, it allows reproducibility check and screening of a wide range
of brine compositions in a reasonable time frame. Therefore, it is
a relevant tool to identify the most favorable brine compositions
to be tested afterward with more time-consuming techniques, such as
Amott tests and corefloods.