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This paper focused on surfactant evaluation targeting the harsh reservoir conditions (high temperature and high salinity fractured reservoir). Six kinds of surfactants were selected and evaluated i...

In this study, the performance of biosurfactants produced by Enterobacter cloacae (PTCC:1798) and Acintobacter calcoaceticus (PTCC:1318) is investigated and the optimum values of operational parame...

Given that alkaline-polymer flooding features the two mechanisms of the increase in viscosity of injection fluid and the decrease in oil/solution interfacial tension, it is common among chemical fl...

The process of fluid displacement in a microscale of porous media in oil reservoirs rock is affected by several factors. Understanding the effects of factors in multiphase flow mechanisms in porous...

This study focuses on the performance of nanosilica particles in the injected brine with different salt concentrations. For investigating the effect of SiO2-water-salt nanofluid in improving oil re...

Based on the ferrohydrodynamic theory by R.E. Rosensweig and roughness effects by Christensen’s stochastic theory, a mathematical model of ferrofluid lubricated flat (parallel) annular disks (plate...

Water injection as one of the most efficient and worldwide extensively employed approach in homogenous oil reservoirs suffers from early water breakthrough time as well as low oil sweep efficiency ...

The goal of enhanced oil recovery is to improve sweep efficiency in the reservoir by the injection of artificial materials in order to reduce the trapped oil saturation. In this study, the application of an anionic polyacrylamide polymer was investigated for heavy oil recovery based on the results of rheological measurements and oil recovery experiments. The properties of the polymer solution were interpreted by the use of well-known rheological models and oil recovery experiments were performed using a heterogeneous two-dimensional glass micromodel saturated with heavy oil of 270 cP. To provide a better understanding of the microscopic efficiency of the process, analysis of continuously provided pictures during the experiments by the use of image processing technique was performed. Rheological results combined with microscopic observations revealed that the non-Newtonian behavior of the solution enhances the sweep efficiency of the both pore throats and pore bodies. Macroscopic observations showe...

The different techniques such as enhanced oil recovery (EOR) and improved oil recovery (IOR) have been used to enhance oil production. The surfactant flooding is a tertiary oil recovery technique that has been widely used in oil field industry. A variety of surfactant chemicals have been used in which among them the amphoteric type, which has two groups of opposite charges, needs more investigation. In this work, we use cocamidopropyl betaine as an amphoteric surfactant that is used to investigate its influence on the aquifer + hydrocarbon system. The effects of surfactant concentration, salinity, and hydrocarbon type on the phase behavior of the various saline aqueous-hydrocarbon mixtures are investigated. Moreover, the surfactant flooding is carried out using a glass micromodel. Thus, to investigate the wettability, the contact angle is also measured for the present system that it is an influential factor in oil recovery. First, by increasing salinity from 0 wt% to 20 wt% in n-hexadecane, the ph...

To gain a better understanding of the migration-plugging properties and plugging mechanism of microfoam, micromodel tests were conducted to investigate the factors controlling the bubble size and plugging mechanism of microfoam. The resistance factor, plugging ratio, and matching factor between average bubble diameter of microfoam and pore-throat diameter of core were introduced to characterize the migration-plugging properties of microfoam by core displacement experiments. The results showed that the average bubble diameter of microfoam could be tuned from 8.6 to 57.9 µm by changing the gas liquid ratio and the sandpack foam generator permeability. Microfoam showed both better injectivity and deep plugging capacity when the matching factor was 1.35–1.87 and the gas liquid ratio was 1:2–1:1. Microfoam would create a temporary blocking zone in the high permeable region through bubble accumulation, and the subsequent microfoam would flow through the low permeable region directly or by means of elast...

To promote the application of strain FY-07 in oilfield development, experiments were performed on the mechanism of microscopic profile control using an etched glass micromodel. The physical simulat...

Nanotechnology has the potential to profoundly change enhanced oil recovery and to improve mechanism of recovery, and it is chosen as an alternative method to unlock the remaining oil resources and applied as a new enhanced oil recovery method in last decade. The objective of this research is identification of potential of nanotitanium dioxide as an appropriate agent for improving the efficiency of surfactant flooding in five-spot glass micromodels. In this work a series of solvent injection experiments was conducted on horizontal glass micromodels at same conditions. Surfactant solutions and newly developed nanosurfactant solutions with 1600–2000 ppm sodium dodecyl sulfate were tested. Observations showed that nanotitanium dioxide has appropriate performance in enhancing the oil recovery at surfactant solution, near critical micelle concentration conditions. Also The results of experiments illustrated improvement of heavy oil recovery in micromodel test with nanotitanium dioxide (51.0%).

Polymer-surfactant flooding is one of the most novel chemical enhanced oil recovery methods. Application of Nano particles in enhanced oil recovery has attracted much interest as well. This work concerns the application of Nano particles to increase the efficiency of polymer-surfactant flooding in heavy oil five-spot systems. In this investigation, micromodel setup was used to monitor the role of Nano particles on wettability alteration during polymer-surfactant floods. Two common Nano particles, SiO2 and TiO2 as well as HPAM and SDS as commercial chemicals in enhanced oil recovery, were used to create five solutions containing Nano particles at different levels of concentration. Then, contact angle tests and flooding tests were performed by taking microscopic/macroscopic pictures. According to the results, since SiO2 Nano particle decrease the contact angle more severely, it results in a higher oil recovery. Although this decrease is more when SiO2 is dispersed in water, due to its better absorpt...

In this paper, we attempted to prepare microfoam by using a sandpack filled with glass beads with co-flowing gas and foaming solution, the microfoam stability and effectiveness in improving profile control capacity at micromodel and pore media were evaluated by micromodel tests and double-core experiments. The results of micromodel tests showed that microfoam stability was increased with increasing xanthan gum concentration due to a higher solution viscosity and viscoelasticity of liquid film. The xanthan gum-stabilized microfoam had a longer propagation distance through the low permeable region of heterogeneous micromodel at time of breakthrough than common microfoam, the optimum performance of microfoam for fluid diversion was multiple bubble trapping and mobilization rather than lamella division. According to the results of double-core experiments, the microfoam could plug the high permeability sandpack and improve the sweep efficiency in the low permeability sandpack, which could improve the water inj...

The nanotechnology has been widely used in several other industries, and the interest in the oil industry is increasing. Nanotechnology has the potential to profoundly change enhanced oil recovery (EOR) and to improve mechanism of recovery, and it chosen as an alternative method to unlock the remaining oil resources and applied as a new EOR method in last decade. Conventional production procedures give access to on average only one-third of the original oil in place, the use of surfactants and polymers allows for recovery of up to another third of this oil. Chemical flooding is of increasing interest and significance due to high oil prices and the need to increase oil production. Objective of this research is Identification of potential of nanoclay as an appropriate agent for improving the efficiency of surfactant polymer flooding in five-spot glass micromodels. In this work a series of solvent injection experiments was conducted on horizontal glass micromodels at same conditions. Observations showed that...

SiO2, NiO, and Fe3O4 nanoparticles are used for absorb asphaltene and prevent their precipitation. For the experiment, water and nanoparticle featured water are injected into micromodel that contained the synthetic oil. The synthetic oil includes asphaltenic components and n-heptane, and volume percentage of each one differs in every experiment. The results show that when n-heptane volume percentage is higher, asphaltene aggregation is more when water is injected. Although, during nanoparticle featured water injection when there is higher n-heptane volume percentages, asphaltene are absorbed on nanoparticle surfaces, which prevents precipitation. Also, it was obtained that SiO2 is the most efficient nanoparticle for this purpose that leads to the maximum recovery.

Dispersion phenomena of miscible displacement processes conducted on porous media have been investigated by many researchers in different engineering field in the past 50 years. In microscopic scale, the pore size distribution has been shown to cause dispersion of two miscible displacement fluids flowing through laboratory core scale. In field scale, the heterogeneity of reservoir formation has been shown to be a main cause of dispersion. One of the heterogeneities of reservoir formation is the presence of networks of fractures. The roles of network fractures on dispersion have not been investigated in enhanced oil recovery miscible displacement processes. In this work, the effect of fractures on dispersion was investigated by conducting miscible displacement laboratory tests on micromodels. The tests were performed under two different injection rates with two different fracture orientations. The results show that breakthrough time is reduced when the fracture is present in the micromodel. Higher pore vol...

During miscible displacements in fractured porous media, one of the most important factors that plays a significant role in oil production is the matrix-fracture interaction. In this work, a series of hydrocarbon injection experiments have been performed on a fractured glass micromodel that was designed specifically to study matrix-fracture interaction. A high quality image analysis method was used to determine the fluid flow behavior, solvent front movement, and viscous fingering associated with solvent movement in matrix and fractures. Observations showed that in the case of unit viscosity ratio, the injection rate increased the slope of recovery curve and consequently improved the final oil recovery. However, when using a viscosity ratio of 65, the injection rate increased the oil recovery at earlier times due to the breakthrough and fracture drainage. At later times, diffusion and dispersion became dominant and oil recovery decreased. Studying the effect of molecular diffusion revealed that by using a...

A random distribution micromodel was developed in order to predict the properties of WC–Co cemented carbides. MATLAB and VC++ were hybrid programmed to extract the necessary information for modelling the microstructure from scanning electron microscopy images. By analysing the distribution regularity of the microstructural parameters, the randomness characterisation of the microstructure of WC–Co cemented carbides was accomplished using probability density function. The parameterised model based on ‘random method’ was developed, in which the random distribution characteristics of microstructural topology parameters, such as average grain diameter, major axis, minor axis, centroid and grain orientation, were considered, with Co volume fraction freely controlled. The representative volume element (RVE) size was determined using the moving window method, with average grain diameter distribution as the evaluation criterion. It was found that the RVE should contain ∼120 grains. The RVE was directly imp...

Severe viscous fingering during water flooding of heavy oil leaves a large amount of oil untouched in the reservoir. Improving sweep efficiency is vital for enhancing heavy oil recovery. This study presented a laboratory study for improving sweep efficiency by alkaline flooding in heavy oil Reservoirs. This included glass-etched micromodel flooding tests, one-dimensional flooding experiments and three-dimensional physical model study. The micromodel tests show that W/O droplet flow plays a prominent role in the alkaline flooding to improve sweep efficiency. There is a minimum alkaline concentration that generates the W/O droplet flow, and the W/O droplet flow is more obvious with the alkaline concentration increasing. A series of flood tests were conducted using 325 mPa · s, 2000 mPa · s, and 3950 mPa · s heavy oils to assess the effectiveness of W/O droplet flow in alkaline flooding for enhanced heavy oil recovery. The flood tests results demonstrate the considerable potential for improved heavy oil reco...

Gravity drainage is the main production mechanism in the gas invaded zone in naturally fractured reservoirs. However, there are large ambiguities and complexities, resulting from the dynamic of oil depletion from matrix blocks toward the fracture network. Visualization of drained oil at pore scale using glass micromodels provides the opportunity to better understand the effects of different parameters which might affect oil recovery from fractured reservoirs. In this work a micromodel apparatus generated by laser etching is used to perform some gravity drainage tests on the network patterns. The experiments were performed on double block systems using crude oil. The block to block interactions and the formation and changes of capillary bridges between matrix blocks were visually investigated. A suitable empirical model of gravity drainage is used for the prediction and evaluation of experimental data. The empirical model will be used for sensitivity analysis of fracture dip angle which might affect oil re...

A surfactant flooding technique is developed to reduce the amount of residual oil saturation by reducing interfacial tension between multiple phases. Using surfactant flooding in the case of high viscosity oil has been successful, whereas there has not been a complete study of efficiency of this method when dealing with low viscosity oil. In the present study, to investigate the behavior of surfactant flooding in low viscosity oil, the transparent material (glass) was used to construct a micromodel and to study various features of micro-displacement. By implementing a micromodel, the displacement of the fluid and menisci was observed and investigated with the aid of high resolution images. In this work, three types of quarter five-spot glass micromodel patterns were designed and developed, and considered as porous medium. These patterns were saturated with a light and low viscosity oil sample from an Iranian fractured reservoir, and then flooded by surfactant slug in low pressure and low temperat...

Liquid bridges are believed to play an important role in improving the recovery of fractured reservoirs. However, little is known about the stability of liquid bridges in fractured media at the pore scale. In this work, a glass micromodel representing a stack of two blocks was used at different tilt angles to monitor the frequency and stability of liquid bridges formed during free-fall gravity drainage as a function of tilt angle. It was observed that by increasing the tilt angle, the liquid bridge frequency decreased but its stability increased. This resulted in higher ultimate recovery. In addition, it was found that during the first half of the experiments, the number of bridges was higher but their stability was lower than during the second half of the tests. Moreover, no more than one stable liquid bridge was observed at tilt angles above 20°, and the bridge cross-sectional area was gradually decreased as the stability was maintained. A sequence of bridges that were formed and broken one aft...

Alkali and alkali/surfactant displacing agents are designed for two kinds of heavy oil. Results of emulsifying capacity, dynamic interfacial tension (IFT) and water-wet core flooding tests show that, although alkaline/surfactant systems exhibit better capacity in emulsification and IFT reduction, oil recovery values of alkaline/surfactant flooding are lower than those of alkaline flooding. Glass-etched micromodel tests further demonstrate that, when alkaline solution penetrates into the oil phase, water streams break into ganglia coating oil film. Water ganglia may be entrapped by narrow throats, consequently presenting a water-oil alternating slug flow. Similar water ganglia also appears in alkaline/surfactant flooding, however, water channeling along the pore surface occurs subsequently, resulting in its relatively lower oil recovery.

Some of the heavy oil reservoirs in Canada, Venezuela, and China under solution gas drive illustrate important features: low gas–oil ratio, high production rates, and very high ultimate oil recovery. It is generally believed that the foamy oil flow is one of the important mechanisms contributing to these unusual performances. A series of two-dimensional etched glass micromodel experiments was carried out to gain an insight into the processes involved in foamy oil flow. In these experiments, the bubble nucleation, migration, coalescence, breakup, and ultimate generation of a continuous gas phase can be observed continuously. On the basis of the experimental analysis, there are two bubble-point pressures in the foamy oil: One is the true bubble-point pressure, and the other is the pseudo-bubble-point pressure. The greater the difference between these two bubble-point pressures, the more stable the foamy oil flow is and the greater the contribution to oil recovery from the foamy oil drive mechanism ...

A polymer flooding technique is developed to reduce the amount of residual oil saturation that cannot be recovered through waterflooding or gas injection processes. Using polymer flooding in the case of high-viscosity oil has been successful due to reducing mobility ratio (M), whereas there is conflict in efficiency of polymer flooding in the case of low-viscosity oil. In this study, to investigate the behavior of polymer flooding in low-viscosity oil, the transparent materials (glass) were used to construct a micromodel and to study various aspects of micro-displacement. By using a micromodel, the displacement of the fluid and menisci was observed and investigated with the aid of images captured by a camera. In this work, two kinds of quarter five-spot glass micromodel patterns were designed and developed and considered as pores medium. These patterns were saturated with light and low-viscosity oil samples from an Iranian fractured reservoir and then flooded by a polymer slug in low-pressure and...

In this work a series of hydrocarbon solvent injection experiments was performed on glass micromodels with different throat orientations that were initially saturated with crude oil at several fixed flow rate conditions. The solvent concentration as a function of location and time was measured using image analysis of color intensity of continuously provided pictures during the injection process. The provided concentration calibration curve of solvent in crude oil was used for back-calculating the solvent concentration along the dispersion zone. The longitude and transverse dispersion coefficients were determined by fitting the results of the mathematical model to the experimental data. It was found that the longitude dispersion decreased when the throat orientation angle increased. In contrast, the transverse dispersion increased. In addition, two trends were observed in variation of longitudinal and transversal dispersion versus Pe. For Pe > 50, the longitude and transverse dispersivities were e...

In this work a series of solvent injection experiments was conducted on horizontal glass micromodels at several fixed flow rate conditions. The micromodels were initially saturated with heavy crude oil. The produced oil as a function of injected volume of solvents was measured using image analysis of the continuously provided pictures. In order to investigate the macroscopic behavior of the process in different media, several fractured, with constant width, and nonfractured five-spot micromodels were designed and used. The measured data have also been used for verifying and developing a simulation model that was later used for sensitivity analysis of some parameters that affect oil recovery. The results show that when the fracture spacing increased, the oil recovery decreased. In contrast, as the fracture orientation angle (the angle with the mean flow direction) or solvent viscosity increased, the oil recovery increased. A critical value for the ratio of connate water saturation to the oil volum...

Despite numerous experimental studies, there is a lack of fundamental understanding on how the chemical composition of a co-solvent at different wettability conditions might affect the pore-scale events and oil recovery efficiency in 5-spot models. In this study visualization of solvent injection experiments performed on a one-quarter five spot glass micromodel, which was initially saturated with the crude oil. One hydrocarbon solvent was considered as base, and four other groups of commercial chemicals, as well as their mixtures, were used as co-solvents. Microscopic and macroscopic displacement efficiency of solvent mixtures in both strongly water-wet and oil-wet media has been studied. It has been observed that small aggregates of asphaltene can improve oil recovery to some extent during early stages of solvent injection. Different groups of chemicals showed various effects on oil recovery based on their nature. An optimum mixture with some percent of commercials containing alcohol group with ...

Chemical flooding is an attractive approach to improve both microscopic and macroscopic sweep efficiencies due to the synergistic effects of interfacial tension reduction and mobility control improvement. In this study, the effect of two hydrophilic silica nanoparticles with different particle sizes of 7 and 25 nm on the phase behavior of surfactant solution and rheological behavior of polymer solution was investigated. Oil recovery experiments for the formulations with high viscosity and low interfacial tension were also conducted in a quarter five-spot glass micromodel. Phase behavior tests indicated that interfacial tension decreased dramatically (0.002 mN/m) due to the presence of smaller dispersed silica nanoparticles in surfactant solution. Rheological experiments showed that larger silica nanoparticles improve the viscosity of low molecular-weight polymer solution more than 20 cP in a wide range of shear rates. Oil recovery experiments revealed that dispersed silica nanoparticles in both su...

This paper describes an interface between a thermodynamic calculation of phase diagram parameters for multicomponent alloys and a micromodel for calculation of fraction solid and enthalpy in the preprocessing module of a commercial FEM software package. This calculation can be performed under LEVER (equilibrium), SCHEIL (complete diffusion in liquid and no diffusion in solid), and BACK-DIFFUSION (complete liquid mixing with solid diffusion for a fixed cooling rate) conditions. The calculated data can be used as thermophysical properties for a subsequent solidification modeling study of a casting. Simulation studies are performed on three high-Cr white cast irons using SCHEIL and LEVER models. A general agreement is found while comparing thermal parameters, carbide volume fractions, and types of phases that appear between simulated and published experimental data. This study also highlights the potential experimental error and limitation.

Drying experiments are carried out in two-dimensional etched networks under quasi-isothermal conditions. The evolution of phase distributions within the network are visualized and compared to numerical discrete simulations. The phase evolution determined by numerical simulations agrees very well with experimental results. However, the comparison between numerical and experimental drying kinetics does not show good agreement. The differences are explained by the presence of liquid films on the micromodel walls and edges during drying. These films are not taken into account in the numerical model.

Videomicroscopy was used with a novel bead-pack micromodel to observe directly movement and distribution of toluene in the unsaturated zone during its initial entry, subsequent water infiltration and gravity drainage, and externally imposed fluctuations in the water table. In a partially water-saturated medium gravity drainage of toluene to the water table occurred as thin layers which flowed along continuous air-water interfaces, leaving a very low residual saturation. Experiments with presaturated toluene and water and with n-butanol and water showed that such drainage was faster and more complete for liquids that spread spontaneously on water, i.e., that had zero contact angle. However, whatever the spreading properties, drainage in such layers did not occur at all unless the gravitational driving force for downward flow exceeded the vertical capillary pressure gradient opposing flow. Toluene trapped in zones of low permeability or hydraulic conductivity during the first infiltration of water following toluene injection was not displaced during subsequent water infiltration and gravity drainage cycles. Fluctuations in the water table redistributed the toluene, in some cases trapping mobile toluene while in others mobilizing trapped toluene. The implications of these results for contamination and cleanup of ground water aquifers are discussed