NANOHYDROMECHANICS - Foundations of Nanotechnology: Pore Size in Carbon-Based Nano-Adsorbents - page 226

5.1 NANOPHENOMENON IN OIL PRODUCTION
Oil-saturated layers are porous materials with different pore sizes, pore channels
and composition of rocks that define the features of interaction formation and
injected fluids with the rock. Taking the mentioned into account we can conclude
that the displacement of oil from oil fields in production wells is not a mechanical
process of substitution of oil displacing it with water, but a complex physical-
chemical process in which the decisive role is played by the phenomenon of ion
exchange between reservoir and injected fluids with the rock, i.e. nanoscale phe-
nomena.
The mechanism of displacement of oil in the reservoir and its recovery is
largely determined by the molecular-surface processes occurring at phase inter-
faces (the rock-forming minerals-saturate the reservoir fluids and gases-displac-
ing agents). Therefore, the problem of wettability is one of the major problems in
oil and gas field of nanoscience.
As the clay is an ultra-system, a huge amount of research on regulation of the
position of clay minerals in porous media with good reason can be attributed to
nanoscience. To it also should be included the study of gas hydrates, a number
of processes regulating the properties of the pumped oil and gas trapped water,
water-oil preparation.
Filteringoilin reservoirs at a depth of13 km of hard rock is determined by the
hydro dynamics oft he Darcy law. Of the Navier-Stokes equation

v

� �

( )

r + ∇⋅ vv = −∇ + m p v

€ ‚

ƒ „

t (5.1)

At very low Reynolds numbers it follows that we can neglect the inertial forc-
es and simplify viscous friction:

v

−∇ − m p = 0

, (5.2)

d

2

where, d- characteristic pore size. Equation (5.2) yields Darcy's law

K

v =− ∇

m

p

, (5.3)

where, K = d 2 - permeability of the medium, а- viscosity of the fluid.
Typical permeability values range from 5 mDto 500 mD. The permeability of
coarse-grained sandstone is

, the permeability of dense sand stone

− 8 − 9 2

10 − 10 sm

around 10 s − . Medium with the permeability 1 sP passes of fluidf low with a

viscosity 1 s P at a pressure gradient 1/

2 2

aym sm .
During filtration oil fills and moves in the pores with the size of 1 mkm . In
order to displace oil from the reservoir one should have a medium with density
and viscosity of oil and the size of 1 mkm .
It seems that it is necessary to conduct experimental and theoretical studies
of possible ways to obtain microbubbles nanoscale environments, to make the