5 research outputs found
Adsorption and Orientation of Ionic Liquids and Ionic Surfactants at Heptane/Water Interface
Molecular
dynamics simulation of heptane/ionic-liquid/water system was performed
to study the effect of hydrophobic and hydrophilic ionic liquids (ILs)
on the interfacial structure of heptane/water as a model for oil/water
systems. The results are compared with the simulated water/sodium-dodecyl-sulfate
(SDS)/heptane interface. Also, the self-assembly and orientation of
ILs and SDS molecules at heptane/vapor interface are studied. We observed
that the behavior of these surfactants at heptane/water and heptane/vapor
interfaces is very different. The computed density profiles provide
a detailed view of the interfacial structure and a route to discuss
quantitatively how the oil and water phases organize the surfactant
molecules. The effect of ILs [C<sub><i>n</i></sub>mim]ÂCl
and [C<sub><i>n</i></sub>mim]ÂPF<sub>6</sub> (with <i>n</i> = 4, 8, and 12) and SDS on the interfacial tension of
heptane/water was simulated and compared at <i>T</i> = 343.15
K. The results indicate that ILs with long alkyl chain could behave
similar to a conventional surfactant
Effect of Resins on Asphaltene Deposition and the Changes of Surface Properties at Different Pressures: A Microstructure Study
Asphaltene deposition has hindered
oil production from asphaltenic
oil reservoirs through deposition in reservoir rock and surface facilities.
This paper investigates the effect of resin on asphaltene deposition
at different pressures. To investigate the asphaltene deposition in
the presence of resins at reservoir temperature and different pressures,
a pressure, volume, and temperature (PVT) visual cell was designed.
A high-resolution microscope and image processing software were used
to detect and determine the amount of deposited asphaltene as well
as its size distribution at different conditions. Two types of Iranian
crude oils with different potential of deposition (low and high) were
used in this work. In the first stage, the amount of asphaltene deposition
and the changes of surface properties were recognized through the
depressurizing process with and without the presence of resins in
the fluid. The wettability changes as a sign of surface properties
were studied by contact angle measurement, and also for further investigation,
the atomic force microscopy (AFM) technique was used. The results
verify that the amount of asphaltene deposition increases when the
pressure increases and the quantity of asphaltene deposition decreases
as the resin/asphaltene ratio in these samples increases. At high
ratios of resin/asphaltene, the asphaltene was found to be more stable.
However, the results showed that, as the pressure increases, the stability
of asphaltene decreases more than expected. The surface property changes
indicate that, in the presence of resins, the surfaces become more
water-wet and their roughness decreases
Effects of Native and Non-Native Resins on Asphaltene Deposition and the Change of Surface Topography at Different Pressures: An Experimental Investigation
Asphaltene
deposition during oil production and transportation
causes extensive damage to reservoirs and wellhead equipment. In this
study, the effects of native and non-native resins as well as those
of their mixtures on the asphaltene deposition process are investigated.
A novel pressure, volume, and temperature (PVT) visual cell is used
to check the effect of resin on asphaltene deposition at different
pressures and reservoir temperatures. Two Iranian crude oil samples
with different potentials of asphaltene deposition (low and high)
were used in these tests. During depressurizing in the presence of
native and non-native resins, the amount of asphaltene deposited was
measured. To monitor any changes in surface topography, the atomic
force microscopy (AFM) technique was used in this study. The results
show that the amount of asphaltene deposited decreases as the amount
of resin increases; however, less asphaltene is deposited when the
resin mixture is used than when the native resin is used. At high
ratios of resin to asphaltene, the stability of asphaltene is higher,
but as the pressure increases, the stability of the asphaltene decreases
more than expected. The surface property changes indicate that in
the presence of the resin mixture the surfaces are less affected
Temperature and Composition Effect on CO<sub>2</sub> Miscibility by Interfacial Tension Measurement
Crude
oil reservoirs have different temperatures, compositions, and pressures,
therefore oil recovery performance by CO<sub>2</sub> injection varies
from one case to another. Furthermore, it is predicted that lower
interfacial tension between injected CO<sub>2</sub> and reservoir
fluid results in more oil recovery. In this study, we investigate
the effect of temperature on the equilibrium interfacial tension between
CO<sub>2</sub> and three different oil fluids at different pressures.
Also minimum miscible pressure (MMP) is measured by the vanishing
interfacial tension (VIT) technique to determine the temperature effect
on the CO<sub>2</sub> miscible gas injection. The results on different
pure and mixtures of hydrocarbon fluids show that for pressures up
to 5.2 MPa, the higher the temperature was, the lower was the interfacial
tension (IFT) measured. However, for the cases with pressure higher
than 5.2 MPa, as the temperature was increased, the IFT increased
too. In addition the VIT technique is used to measure the MMP of CO<sub>2</sub> and pure paraffin; the heavier paraffin was, the higher was
the MMP noticed. Also, we have learned that paraffin groups have an
important effect on multicomponent interfacial tension behavior
Investigating the Effects of Temperature, Pressure, and Paraffin Groups on the N<sub>2</sub> Miscibility in Hydrocarbon Liquids using the Interfacial Tension Measurement Method
In
this study, interfacial tension measurement (IFT) is utilized
to assess the impact of temperature, pressure, and paraffin type on
a nitrogen injection process as an efficient enhanced oil recovery
method. The pure and equilibrium densities of oil in contact with
nitrogen are examined to find IFT behavior and gas solubility in oil.
The minimum miscible pressure (MMP) of different systems has been
measured using the vanishing interfacial tension technique. The experimental
results show that IFT decreases linearly with pressure, with two different
slopes. The results indicate that IFT values decrease linearly with
temperature at different pressure conditions. The obtained IFT values
for (hexadecane + N<sub>2</sub>) and (diesel fuel + N<sub>2</sub>)
systems are close to each other. The variation in IFT of nitrogen–paraffin
systems by pressure shows a similar slope to that of the N<sub>2</sub> and oil mixture (diesel fuel) system. The MMP of different systems
was observed to decrease with increasing temperature. The results
of this work show that nitrogen injection would be an effective enhanced
oil recovery process in high-pressure and high-temperature oil reservoirs