Wettability
Alteration in Low-Permeability Sandstone
Reservoirs by “SiO<sub>2</sub>–Rhamnolipid” Nanofluid
Di Wang
Shanshan Sun
Kai Cui
Hailan Li
Yejing Gong
Jirui Hou
Zhongzhi Zhang
10.1021/acs.energyfuels.9b01930.s001
https://acs.figshare.com/articles/journal_contribution/Wettability_Alteration_in_Low-Permeability_Sandstone_Reservoirs_by_SiO_sub_2_sub_Rhamnolipid_Nanofluid/11310509
The wettability condition of a rock’s surface
is an enormous
parameter for enhanced oil recovery (EOR) in low-permeability reservoirs.
It determines the spreading of injected water and the adhesion of
residual oil on rock surfaces. In this study, a new nanofluid composed
of silica nanoparticles and rhamnolipid in brine was utilized as an
effective agent to alter the wettability of a rock’s surface.
In order to obtain rock surfaces with different initial wettabilities,
hexamethyldisilazane (HMDS) was used for the sample preparation. The
measurement of three-phase contact angles for water/air/rock and brine/oil/rock
were performed to explore the contact situation between a rock surface
and movable fluids, and the spontaneous imbibition test researched
the process of oil recovery with nanofluid. By evaluating the experimental
measurements, nanofluid showed a significant potential in wettability
alteration from oil-wet toward water-wet state, which is an important
mechanism for “scraping” oil drops from a rock surface
during nano-EOR process. Moreover, a total of nine coreflooding tests
were performed to investigate the effects of rock wettability on waterflooding
and nanofluid flooding, respectively. The results revealed that an
intermediate-wet state of a rock’s surface is in favor of the
oil recovery especially for waterflooding, and nanofluid, resulting
in an additional 5.3–6.8% increments in oil recovery compared
to conventional waterflooding. In conclusion, nanofluids show a significant
potential for EOR from low-permeability cores, implying a wide application
in oil fields.
2019-12-03 15:25:23
EOR
three-phase contact angles
HMDS
nanofluid
rock surface
oil recovery
rock surfaces
Low-Permeability Sandstone Reservoirs
waterflooding
wettability