Application of Nanoparticles-Based Technologies in the Oil …
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This wedge-shaped film appears because of the structural disjoining pressure created
by the osmotic pressure created during injection of the nanofluids (Mcelfresh et al.
2012). When the nanofluids are injected bottom-hole the injection pressure creates a
uniform layer in a confined region ahead due to exerted pressure and the layer tends
to arrange with more NPs in the flow. The entropy of this arrangement increases with
increasing number of NPs and further results in an additional disjoining pressure
exerted at the interface than that of the bulk liquid (Aveyard et al. 2003; Chengara
et al. 2004). A higher concentration of NPs raises Brownian motion and electrostatic
repulsions between the particles generating the disjoining pressure. The size of NPs,
amount, composition of base fluid (salinity levels), rock characteristics all affects the
disjoining pressure. For example, larger amount of NPs increases the force to 50,000
psi at the vertex (Aveyard et al. 2003).
3.1.6 Limiting Asphaltene Precipitation
Asphaltene precipitation is a major problem encountered during primary recovery
and EOR methods leading to deposits in the porous media (Papadimitriou et al. 2007;
Solaimany-Nazar and Zonnouri 2011). Whereas wettability alteration contributes
toward higher EOR recovery potential, precipitation of asphaltene causes plugging
of the reservoir, alteration of wettability from water-wet toward more oil-wet and
lowering of the relative permeability of the oil (Nghiem et al. 1998; Pina et al. 2006).
Many researchers have found NPs as a solution to this problem without leading to
any environmental pressure. Tarboush et al. found that NiO NPs have a higher affinity
toward asphaltene leading to the uptake of this particles and stabilizing precipitation
(Tarboush and Husein 2012). Similarly, testing of SiO 2 –Al 2 O 3 NPs by Alomair
revealed that as the concentration of NPs is increased, it delayed the precipitation
further (Alomair et al. 2014). Kazemzadeh et al. additionally determined how SiO 2 ,
NiO and Fe 3 O 4 NPs were adsorbed on the surface of asphaltene molecules, which
significantly reduced the flocculation in the porous media (Kazemzadeh et al. 2015).
3.2 Nanoemulsions
Nanoemulsions are emulsions stabilized by NPs with a droplet size ranging from
50 to 500 nm. The physicochemical properties of these micro-droplets (<100 nm)
can help successfully enhance the EOR efficiency by recovering. These emulsions
are much more stable than conventional emulsions which are stabilized by surfactants (Mandal et al. 2012). Also, these NPs stabilize the nanoemulsions by forming a
kinetically controlled system which can withstand extreme conditions (higher temperature, salinity and increased pressures) by retaining their morphology even with
change in oil volume fractions (Binks and Lumsdon 2000). The size of nanoemulsions can even help them to penetrate through the thief zones and pore throats with
lower rates of adsorption (Zhang et al. 2010). Additionally, nanoemulsions have a
269
This wedge-shaped film appears because of the structural disjoining pressure created
by the osmotic pressure created during injection of the nanofluids (Mcelfresh et al.
2012). When the nanofluids are injected bottom-hole the injection pressure creates a
uniform layer in a confined region ahead due to exerted pressure and the layer tends
to arrange with more NPs in the flow. The entropy of this arrangement increases with
increasing number of NPs and further results in an additional disjoining pressure
exerted at the interface than that of the bulk liquid (Aveyard et al. 2003; Chengara
et al. 2004). A higher concentration of NPs raises Brownian motion and electrostatic
repulsions between the particles generating the disjoining pressure. The size of NPs,
amount, composition of base fluid (salinity levels), rock characteristics all affects the
disjoining pressure. For example, larger amount of NPs increases the force to 50,000
psi at the vertex (Aveyard et al. 2003).
3.1.6 Limiting Asphaltene Precipitation
Asphaltene precipitation is a major problem encountered during primary recovery
and EOR methods leading to deposits in the porous media (Papadimitriou et al. 2007;
Solaimany-Nazar and Zonnouri 2011). Whereas wettability alteration contributes
toward higher EOR recovery potential, precipitation of asphaltene causes plugging
of the reservoir, alteration of wettability from water-wet toward more oil-wet and
lowering of the relative permeability of the oil (Nghiem et al. 1998; Pina et al. 2006).
Many researchers have found NPs as a solution to this problem without leading to
any environmental pressure. Tarboush et al. found that NiO NPs have a higher affinity
toward asphaltene leading to the uptake of this particles and stabilizing precipitation
(Tarboush and Husein 2012). Similarly, testing of SiO 2 –Al 2 O 3 NPs by Alomair
revealed that as the concentration of NPs is increased, it delayed the precipitation
further (Alomair et al. 2014). Kazemzadeh et al. additionally determined how SiO 2 ,
NiO and Fe 3 O 4 NPs were adsorbed on the surface of asphaltene molecules, which
significantly reduced the flocculation in the porous media (Kazemzadeh et al. 2015).
3.2 Nanoemulsions
Nanoemulsions are emulsions stabilized by NPs with a droplet size ranging from
50 to 500 nm. The physicochemical properties of these micro-droplets (<100 nm)
can help successfully enhance the EOR efficiency by recovering. These emulsions
are much more stable than conventional emulsions which are stabilized by surfactants (Mandal et al. 2012). Also, these NPs stabilize the nanoemulsions by forming a
kinetically controlled system which can withstand extreme conditions (higher temperature, salinity and increased pressures) by retaining their morphology even with
change in oil volume fractions (Binks and Lumsdon 2000). The size of nanoemulsions can even help them to penetrate through the thief zones and pore throats with
lower rates of adsorption (Zhang et al. 2010). Additionally, nanoemulsions have a