Insights Into Mobilization of Shale Oil by Use of Microemulsion

SPE Journal ◽  
2016 ◽  
Vol 21 (02) ◽  
pp. 613-620 ◽  
Author(s):  
Khoa Bui ◽  
I. Yucel Akkutlu ◽  
Andrei Zelenev ◽  
Hasnain Saboowala ◽  
John R. Gillis ◽  
...  
Keyword(s):  
Oil Recovery ◽  
The Other ◽  
Dynamics Simulation ◽  
Shale Oil ◽  
Water Interface ◽  
Fractional Flow ◽  
Flow Measurements ◽  
Oil Film ◽  
Other Hand ◽  
Oil Water

Summary Molecular-dynamics simulation is used to investigate the nature of two-phase (oil/water) flow in organic capillaries. The capillary wall is modeled with graphite to represent kerogen pores in liquid-rich resource shale. We consider that the water carries a nonionic surfactant and a solubilized terpene solvent in the form of a microemulsion, and that it was previously introduced to the capillary during hydraulic-fracturing operation. The water has already displaced a portion of the oil in place mechanically and now occupies the central part of the capillary. The residual oil, on the other hand, stays by the capillary walls as a stagnant film. Equilibrium simulations show that, under the influence of organic walls, the solvent inside the microemulsion droplets enables not only the surfactant but also the complete droplet to adsorb to the interfaces. Hence, delivering the surfactant molecules to the oil/water interface is achieved faster and more effectively in the organic capillaries. After the droplet arrives at the interface, the droplet breaks down and the solvent dissolves into the oil film and diffuses. This process is similar to drug delivery at nanoscale. Using nonequilibrium simulations based on the external force-field approach, we numerically performed steady-state flow measurements to establish that the solvent and the surfactant molecules play separate roles that are both essential in mobilizing the oil film. The surfactant deposited at the oil/water interface reduces the surface tension and acts as a linker that diminishes the slip at the interface. Hence, it effectively enables momentum transfer from the mobile water phase to the stagnant oil film. The solvent penetrating the oil film, on the other hand, modifies flow properties of the oil. In addition, as a result of selective adsorption, the solvent displaces the adsorbed oil molecules and transforms that portion of the oil into the free oil phase. Consequently, the fractional flow of oil is additionally increased in the presence of solvent. The results of this work are important for understanding the effect of microemulsion on flow in organic capillaries and its effect on shale-oil recovery.

scholarly journals IN SILICO POTENTIAL ANALYSIS OF X6D MODEL OF PEPTIDE SURFACTANT FOR ENHANCED OIL RECOVERY

2018 ◽  
Vol 39 (2) ◽  
pp. 101-106
Author(s):  
Cut Nanda Sari ◽  
Usman Usman ◽  
Rukman Hertadi ◽  
Tegar Nurwahyu Wijaya ◽  
Leni Herlina ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Interfacial Tension ◽  
Molecular Dynamics Simulations ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
Dynamics Simulation ◽  
Coarse Grained ◽  
Water Interface ◽  
Oil Water ◽  
Dynamics Simulations

Peptides and their derivatives can be applied in enhanced oil recovery (EOR) due to their ability to form an emulsion with hydrophobic molecules. However, peptide research for EOR application, either theoretical or computational studies, is still limited. The purpose of this research is to analyse the potency of the X6D model of surfactant peptide for EOR by molecular dynamics simulations in oil-water interface. Molecular dynamics simulation using GROMACS Software with Martini force field can assess a peptides ability for self-assembly and emulsification on a microscopic scale. Molecular dynamics simulations combined with coarse grained models will give information about the dynamics of peptide molecules in oil-water interface and the calculation of interfacial tension value. Four designs of X6D model: F6D, L6D, V6D, and I6D are simulated on the oil-water interface. The value of interfacial tension from simulation show the trend of F6D L6D I6D V6D. The results indicate that V6D has the greatest reduction in interfacial tension and has the stability until 90C with the salinity of at least 1M NaCl.

Application of Molecular Simulations to CO2-Enhanced Oil Recovery: Phase Equilibria and Interfacial Phenomena

SPE Journal ◽  
2013 ◽  
Vol 18 (02) ◽  
pp. 319-330 ◽  
Author(s):  
Dai Makimura ◽  
Makoto Kunieda ◽  
Yunfeng Liang ◽  
Toshifumi Matsuoka ◽  
Satoru Takahashi ◽  
...  
Keyword(s):  
Phase Equilibria ◽  
Enhanced Oil Recovery ◽  
Oil Recovery ◽  
High Pressures ◽  
Co2 Enrichment ◽  
Interfacial Phenomena ◽  
Interfacial Region ◽  
Water Interface ◽  
Oil Water ◽  
Co2 Eor

Summary Molecular simulation is a powerful technique for obtaining thermodynamic properties of a system of given composition at a specific temperature and pressure, and it enables us to visualize microscopic phenomena. In this work, we used simulations to study interfacial phenomena and phase equilibria, which are important to CO2-enhanced oil recovery (EOR). We conducted molecular dynamics (MD) simulation of an oil/water interface in the presence of CO2. It was found that CO2 was enriched at the interfacial region under all thermal conditions. Whereas the oil/water interfacial tension (IFT) increases with pressure, CO2 reduces the IFT by approximately one-third at low pressure and one-half at higher pressure. Further analysis on the basis of our MD trajectories shows that the O=C=O bonds to the water with a “T-shaped” structure, which provides the mechanism for CO2 enrichment at the oil/water interface. The residual nonnegligible IFT at high pressures implies that the connate or injected water in a reservoir strongly influences the transport of CO2/oil solutes in that reservoir. We used Gibbs ensemble Monte Carlo (GEMC) simulation to compute phase equilibria and obtain ternary phase diagrams of such systems as CO2/n-butane/N2 and CO2/n-butane/n-decane. Simulating hydrocarbon fluids with a mixture of CO2 and N2 enables us to evaluate the effects of N2 impurity on CO2-EOR. It also enables us to study the phase behavior, which is routinely used to evaluate the minimum miscibility pressure (MMP). We chose these two systems because experimental data are available for them. Our calculated phase equilibria are in fair agreement with experiments. We also discuss possible ways to improve the predictive capability for CO2/hydrocarbon systems. GEMC and MD simulations of systems with heavier hydrocarbons are straightforward and enable us to combine molecular-level thinking with process considerations in CO2-EOR.

scholarly journals Molecular Dynamics Simulation of Distribution and Diffusion Behaviour of Oil–Water Interfaces

Molecules ◽  
2019 ◽  
Vol 24 (10) ◽  
pp. 1905 ◽  
Author(s):  
Chengbin Zhang ◽  
Hanhui Dai ◽  
Pengfei Lu ◽  
Liangyu Wu ◽  
Bo Zhou ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Interface Roughness ◽  
Dynamics Simulation ◽  
Water Phase ◽  
Water Molecules ◽  
Water Interface ◽  
Oil Water ◽  
And Diffusion ◽  
Diffusion Behaviors

The distribution and diffusion behaviors of microscopic particles at fluorobenzene–water and pentanol–water interfaces are investigated using molecular dynamics simulation. The influences of Na+/Cl− ions and the steric effects of organic molecules are examined. The concentration distributions of different species, the orientations of oil molecules at the interface, and oil–water interface morphology as well as the diffusion behaviors of water molecules are explored and analyzed. The results indicate that a few fluorobenzene molecules move into the water phase influenced by Na+/Cl− ions, while the pentanol molecules at the interface prefer orientating their hydrophilic groups toward the water phase due to their large size. The water molecules more easily burst into the pentanol phase with larger molecular spaces. As the concentration of ions in the water phase increases, more water molecules enter into the pentanol molecules, leading to larger interface roughness and interface thickness. In addition, a lower diffusion coefficient for water molecules at the fluorobenzene–water interface are observed when introducing Na+/Cl− ions in the water phase, while for the pentanol–water system, the mobility of interfacial water molecules are enhanced with less ions and inhibited with more ions.

Molecular dynamics simulation of four typical surfactants at oil/water interface

2017 ◽  
Vol 39 (9) ◽  
pp. 1258-1265 ◽  
Author(s):  
Peng Shi ◽  
Hui Zhang ◽  
Lin Lin ◽  
Chunhui Song ◽  
Qingguo Chen ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Dynamics Simulation ◽  
Water Interface ◽  
Oil Water

Evaluation of the Interfacial Tension Between a Microemulsion and the Excess Dispersed Phase

1981 ◽  
Vol 21 (05) ◽  
pp. 593-602 ◽  
Author(s):  
E. Ruckenstein
Keyword(s):  
Interfacial Tension ◽  
Oil Recovery ◽  
Phase Inversion ◽  
The Other ◽  
Dispersed Phase ◽  
Middle Phase ◽  
Inversion Point ◽  
Interfacial Tensions ◽  
Dispersed Medium ◽  
Oil Water

Abstract From a consideration of the thermodynamic stability of microemulsions, one can establish a relation between the interfacial tension y at the surface of the globules and the derivative, with respect to their radius re, of the entropy of dispersion of the globules in the continuous medium. Expressions for the entropy of dispersion are used to show that gamma is approximately proportional to kT/r2e, where k is Boltzmann's constant and T is the absolute temperature. Since the environment of the interface between the microemulsion and the excess dispersed medium is expected to be similar to that at the surface of the globules, these expressions are used to evaluate the interfacial tension between microemulsion and excess dispersed medium. Values between 10 and 10 dyne/cm that decrease with increasing radii are obtained, in agreement with the range found experimentally by various authors. The origin of the very small interfacial tensions rests ultimately in the adsorption of surfactant and cosurfactant on the interface between phases. The effect on the interfacial tension of fluctuations from one type of microemulsion to the other, which may occur near the phase inversion point, is discussed. Introduction The system composed of oil, water, surfactant, cosurfactant, and salt exhibits interesting phase equilibria. For sufficiently large concentrations of surfactant, a single phase can be formed either as a microemulsion or as a liquid crystal. In contrast, at moderate surfactant concentrations, two or three phases can coexist. For moderate amounts of salt (NaCl), an oil phase is in equilibrium with a water-continuous microemulsion, whereas for high salinity, an oil-continuous microemulsion coexists with a water phase. At intermediate salinity, a middle phase (probably a microemulsion) composed of oil, water, surfactants, and salt forms between excess water and oil phases. Extremely low interfacial tensions are found between the different phases, with the lowest occurring in the three-phase region. These systems have attracted attention because of their possible application to tertiary oil recovery. It has been shown that the displacement of oil is most effective at very low interfacial tensions.Microemulsions have been investigated with various experimental techniques, such as low-angle X-ray diffraction, light scattering, ultracentrifugation, electron microscopy, and viscosity measurements. These have shown that the dispersed phase consists of spherical droplets almost uniform in size. While it is reasonable to assume that the microemulsions coexisting with excess oil or water contain spherical globules of the dispersed medium, the structure of the middle-phase microemulsion is more complex. Experimental evidence obtained by means of ultracentrifugation indicates, however, that at the lower end of salinity the middle phase contains globules of oil in water, while at the higher end the middle phase is oil continuous. A phase inversion must occur, at an intermediate salinity, from a water-continuous to an oil-continuous microemulsion. The free energies of the two kinds of microemulsions are equal at the inversion point. Since their free energy of formation from the individual components is very small, small fluctuations, either of thermal origin or due to external perturbations, may produce changes from one type to the other in the vicinity of the inversion point. As a consequence, near this point, it is possible that the middle phase is composed of a constantly changing mosaic of regions of both kinds of microemulsions. SPEJ P. 593^

DECOMPOSITION OF C60 MOLECULES ON Si(100)(2 × 1) SURFACE

2000 ◽  
Vol 11 (05) ◽  
pp. 1067-1076
Author(s):  
ŞAKIR ERKOÇ ◽  
ŞENAY KATIRCIOĞLU
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulation ◽  
Phase Change ◽  
Elevated Temperatures ◽  
Model Potential ◽  
The Other ◽  
Dynamics Simulation ◽  
High Coverage ◽  
Other Hand ◽  
Low Coverage

We have investigated the decomposition of C 60 molecules with low and high coverages on Si(100)(2×1) surface at elevated temperatures. We also investigated the decomposition of an isolated C 60 molecule. We employed molecular-dynamics simulation using a model potential. It has been found that C 60 decomposes on Si(100) surface after 1000 K in the case of low coverage (0.11), however in high coverage case (0.67), C 60 molecules decompose after 900 K. On the other hand, isolated C 60 molecule decomposes after 7500 K, interestingly it shows a phase change from 3D to 2D at higher temperatures.

scholarly journals INCREASING OIL RECOVERY APPLYING ELECTRIC STIMULATION ON THE FORMATION

2021 ◽  
Author(s):  
Bahshillo Akramov ◽  
◽  
Sherali Umedov ◽  
Odiljon Khaitov ◽  
Jaloliddin Nuriddinov ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Surface Tension ◽  
Electric Field ◽  
Electric Fields ◽  
Oil Recovery ◽  
Experimental Studies ◽  
Surface Tension Coefficient ◽  
Recovery Factor ◽  
Water Interface ◽  
Oil Water

The work is devoted to increasing the degree of depletion of reserves of longterm exploited hydrocarbon deposits on the basis of the obtained results of theoretical and experimental studies of the application of electrodynamic technologies for stimulating the formation and bottomhole formation zone. The electrolysis of formation fluids, water, oil-bearing rocks, is accompanied by a mass transfer, primary and secondary chemical reactions, the formation of all kinds of salts, alkalis and acids, new organic substances and all kinds of surfactants. Not only the liquid is subjected to electrolysis, but also the oil and gas bearing rocks themselves (solid electrolyte). The magnetic and electrical forces arising during the electric treatment of reservoirs make it possible to effectively drain heterogeneous reservoirs and extract residual oil from non-working layers. The work also carried out experiments to study the effect of the electric field on the surface tension coefficient at the oil-water interface. The circumstance of an abrupt change in the surface tension coefficient at the oil-water interface makes it possible in principle to create conditions in the reservoir that make it possible to slow down the cusping processes by applying an electric field of various magnitudes or, in other words, by regulating the amount of mass transfer. In numerical terms, the oil recovery factor without electrophysical treatment was 52.94%. Under electrophysical impact, the oil recovery factor was 94.12%, i.e. equaled to almost complete extraction of oil from the sample. In the field, this figure, of course, will decrease by 2-3 times, but it remains quite high in comparison with other methods of increasing oil recovery. Thus, the studies performed on samples in laboratory conditions indicate the possibility of using constant electric fields to increase oil recovery from depleted watered formations. Electrochemical treatment of the formation can significantly increase the displacement of oil from the formation. The increase in oil displacement reaches 15-20% and more. With the help of water alone, 58% of the oil (of its total volume in the sand) was displaced from the sand, and under electric field with a voltage of 10 V and 20 V, the total amount of displaced oil, respectively, increased to 67 and 83%. Thus, the laboratory studies performed on the samples also indicate the possibility of using constant electric fields to increase oil recovery from depleted watered formations. The carried out theoretical and experimental studies show the possibility of using the technology of electrochemical and electrothermochemical leaching of oilsaturated rocks to intensify oil production. The effectiveness of the recommended technology is especially noticeable in fields that have entered the final stage of development with a high water cut.

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