Foam Generation Research Articles

Mechanistic foam flow model with variable flowing foam fraction and its implementation using automatic differentiation

Foam injection is an effective method for modifying gas mobility in subsurface flow applications making it ideal for environmental remediation applications. Remediation of contaminated soils/aquifers of nonaqueous phase liquids using foamed surfactant solutions is a viable option but a predictive foam model is needed that is flexible to the addition of more accurate physical descriptions. Such a model is essential to ensure successful operations in soil remediation applications. The objective of this paper is to develop a full-physics, mechanistic transient foam flow model and integrate it into the multiphysics, modular AD-GPRS framework (Automatic Differentiation–General Purpose Research Simulator). We chose AD-GPRS because it allows rapid prototyping and addition of complex physics and modeling strategies. We develop the model ground-up from pore-scale observations and implement a new flowing foam fraction constitutive relation that depends on the local pressure gradient, local permeability, and flowing bubble density. Our model predicts the two flow regimes commonly observed in steady-state pressure gradient measurements: the low-quality regime and the high-quality regime. Additionally, the model is used to match transient experimental results of homogeneous and slightly heterogeneous cores with a wide range of permeability values. The implementation of this model within AD-GPRS allows testing of ideas and modeling strategies as well as inclusion of more complex physics or foam generation kinetics.

Role of Viscous Forces in Foam Flow in Porous Media at the Pore Level

A pore network model is proposed to simulate the complex process of in situ foam generation, destruction, and propagation as a drainage process. Motivated by the need to account for viscous flow effects, which arise from the viscous drag of moving bubbles, the statistical physical method of the modified invasion percolation with memory algorithm is extended. The model is capable of capturing the flow characteristics of (weak) continuous gas and (strong) discontinuous gas foams based on a minimum number of input parameters, that is, pore throat size distribution, regeneration probability, network dimensionality, and size. The dependence of the flowing foam fraction on the applied pressure gradient is predicted. The steady-state relative permeabilities during the simultaneous flow of a liquid and a gas, with lamella generation, destruction, and mobilization by flow displacement, are computed. The proposed model adequately portrays literature results with the decrease in the gas relative permeability upon introduction of foams in agreement with the reported results for similar porous media. The results find application in optimizing the current population balance models and guide foam-based enhanced oil recovery projects.

In-situ formulation of pickering CO2 foam for enhanced oil recovery and improved carbon storage in sandstone formation

Compared to sole gas flooding, foam flooding provides superior mobility control, enhanced sweep, and greatly improved oil recovery from depleted oil reservoirs. However, since most modern oil reservoirs are located at higher depths and further away from foam generation units, it is becoming increasingly difficult to maintain foam stability, especially in modern deeper oil wells. Thus, in this study, an alternative study in foam formulation has been reported. Instead of preparing the foam at the surface and injecting it down the oil well, into the subsurface, the foam can be formed “in situ” by saturating the porous media downhole by foaming agents. The foaming agents in this study consisted of an anionic surfactant, sodium dodecyl sulfate (SDS), and the whole solution was stabilized by the addition of 1000 ppm PAM and varying concentrations of silica nanoparticles (NPs). The formed foam can then be pushed conventionally by chase water and provide increased oil recovery. Increasing NP concentration, initially improved foam stability as a higher number of NPs participated in strengthening the gas bubble. Insitu foam formation was also investigated for improving carbon storage in depleted oilfields. The injection rate of gas and the slug size of the foaming agent were varied to determine gas storage before the breakthrough. A lower flow rate was found to be more conducive for foam formation while increasing slug size had little effect on gas storability in the reservoir.

Highly efficient and tunable miktoarm stars for HIPE stabilization and polyHIPE synthesis

PolyHIPEs, macroporous polymers synthesized within the external phases of high internal phase emulsions (HIPEs), have been developed for a wide range of applications (catalyst supports, tissue engineering, drug delivery) in which the leaching of traditional surfactants can become a significant liability. HIPEs can also be stabilized with relatively small amounts of amphiphilic solid nanoparticles, as well as with miktoarm stars, poly(divinylbenzene) (PDVB) cores bearing different types of polymer arms. In this paper, two types of stars bearing both poly(ethylene oxide) and polyacrylate arms were used to stabilize HIPEs, non-reactive stars and stars bearing reactive methacrylate groups. The 0.1 wt % of stars successfully used to stabilize HIPEs containing styrene and DVB were not enough, at low DVB contents in the HIPE, to provide the crosslinking support needed to resist the capillary stresses generated during drying. However, with sufficient DVB in the HIPE, star contents as low as 0.05 wt % were able to successfully stabilize a HIPE with 90% internal phase and produce a polyHIPE with a density of 0.06 g/cm3. As little as 0.07 wt % stars were enough to stabilize HIPEs containing long side-chain (meth)acrylates and ~0.7 wt % of a crosslinking polyhedral silsesquioxane (POSS) and yield polyHIPEs with densities of around 0.2 g/cm3. These polyHIPEs exhibited rapid shape recovery and recovery ratios of 100% when a temporary shape (a 70% compressive strain) was imposed above the melting point of the crystalline phase. Star stabilization combined with POSS crosslinking enable the generation of tunable shape memory polymer foams.

Parameter calibration of the stochastic bubble population balance model for predicting NP-stabilized foam flow characteristics in porous media

Stochastic Bubble Population (SBP) balance model has been widely applied on investigation of surfactant foam flow characteristics in porous media, while its application on predict nanoparticle (NP)-stabilized foam behavior has not been well refined. There are two empirical parameters in the SBP model, namely, the bubble generation rate Kg and the maximum bubble density nmax. To qualify the SBP model on prediction of the transient NP-stabilized foam propagation behavior, we make the efforts to calibrate the parameters of Kg and nmax based on the literature reported systematic experimental results. Through five sets of simulations in correspondence to the experimental works, it is found Kg has little effect on the pressure drop along the core, while the nmax increases from 200 mm−3 to 8000 mm−3 with the addition of NPs and the increment of NP concentration. Larger nmax values at higher NP concentrations indicates the foam stabilized by NPs has stronger foam structure and therefore leads to a better displacement result. It is concluded that based on the simple but carefully calibrated parameters, SBP model could provide accurate predictions of NP-stabilized foam flow characteristic in porous media.

Effect of phosphate quality on foam generation during the phosphoric acid production process

The presence of organics materials in phosphate ores generates foam during the manufacture of phosphoric acid, thus affecting the production performance and the quality of the products. Today, in the phosphate industry defoamers are used to reduce the negative impact of foam phosphoric production. In the present work, we focused on root cause evaluation for foam generation during the phosphoric acid production process, we evaluated the effect of phosphate rock quality in terms of organic carbon (OC) and carbonate content, on foam generation using a laboratory protocol for foaming ability evaluation. The results show that there is a relationship between the volume of the foam generated and the values of those impurities, while the volume of foam generated is higher when the concentration of OC and Carbonate is high. In our work, we confirm that the foaming ability of the phosphate rock can be avoided if the concentration of organic carbon less than 0.1% and less than 3% for carbonate.

Pilot-scale Culture of adventitious Root for the Production of pharmacology active from medicinal plants: a Mini Review

Plant tissue culture technology is a technique for aseptic culture of plant tissues under artificial culture conditions. It can be used as a means to directly mass-produce of bioactive compounds from different culture systems such as adventitious roots (ARs), hairy root, callus, somatic embryogenesis of medicinal plants. ARs cultures show high root proliferation, biomass production and have the potential to synthesize specific bioactive compounds. ARs can be induced in vitro from various explants, such as leaves, roots, stem, petiole callus, etc. Various parameters such as auxins, nitrous oxide, and light have shown to affect the morphogenesis of ARs. Air-lift bioreactors appear to be ideal for plant cell and organ cultures. They are suitable for the ARs culture of various medicinal plants. To scale-up ARs cultures, the Balloon type bubble bioreactor (BTBB) is reported to be a suitable system for the accumulation of both biomass and bioactive compounds production in numerous various medicinal plants. BTBB provides optimum conditions for growth and bioactive compound accumulation by efficiently controlling the culture environment, foam generation, reducing shear stress, and supplying optimal oxygen. This review summarized a strategy and approach for ARs culture for the production of biomass and secondary metabolites from laboratory to industrial scales by using air-lift bioreactor culture systems.

An extension of the multiple marker algorithm for study of phase separation problems at the mesoscale

Multiphase fluid flow is an active field of research in numerous branches of science and technology. An interesting subset of multiphase flow problems involves the dispersion of one phase into another in the form of many small bubbles or droplets, and their subsequent separation back into bulk phases after this has occurred. Phase dispersion may be a desirable effect, for example in the production of emulsions of otherwise immiscible liquids or to increase interfacial surface area for chemical reactions, or an undesirable one, for example in the intermixing of waste and product phases during processing or the generation of foams preventing gas-liquid decoupling. The present paper describes a computational fluid dynamics method based on the multiple marker front-capturing algorithm – itself an extension of the volume-of-fluids method for multiphase flow – which is capable of scaling to mesoscale systems involving thousands of droplets or bubbles. The method includes sub-grid models for solution of the Reynolds equation to account for thin film dynamics and rupture. The method is demonstrated with an implementation in the OpenFOAM® computational mechanics framework. Comparisons against empirical data are presented, together with a performance benchmarking study and example applications.

Comparative study on interfacial and foaming properties of glycolipids in relation to the gas applied for foam generation.

Glycolipids are biosurfactants with a wide range of structural diversity. They are biodegradable, based on renewables, ecocompatible and exhibit high surface activity. Still, studies comparing glycolipids and conventional surfactants in terms of interfacial properties and foaming performance are lacking. Here, we compared interfacial and foaming properties of microbial and enzymatically synthesized glycolipids to those of the widely-used, conventional surfactant sodium dodecyl sulfate (SDS). The enzymatically produced sorbose monodecanoate, as well as microbially produced di-rhamno-di-lipids exhibited high foam stabilizing properties, similar to those of SDS. However, sophorolipid and mono-rhamno-di-lipids did not produce metastable foams. An appropriate selection of head and tail groups depending on the application of interest is therefore necessary. Then, glycolipids can serve as an ecofriendly and efficient alternative to petroleum-based surfactants, even at substantially lower concentrations than e.g. SDS. Moreover, the influence of three foaming gases on the foaming properties of the glycolipids was evaluated. Slightly higher foam stability and lower coarsening rates were determined for sorbose monodecanoate when using nitrogen as the foaming gas instead of air. Foams generated with carbon dioxide were not metastable, no matter which surfactant was used.

Algorithm for foam generation in plane

We propose a novel algorithm for the construction of the sparse, nonetheless the massive and rigid structure. The generated structures possess two significant properties reminiscent of the metallic foams. Firstly, the weight of the structures can be as low as the percent of the bulk one. Secondly, the structures are mechanically rigid. The structures are necessary for the simulation of the physical models of the foam properties.

ЭКСПЕРИМЕНТАЛЬНАЯ УСТАНОВКА ДЛЯ ОПРЕДЕЛЕНИЯ КРИТИЧЕСКОЙ ИНТЕНСИВНОСТИ ПОДАЧИ ПЕНЫ В РЕЗЕРВУАР С ВЫСОКООКТАНОВЫМ БЕНЗИНОМ

Purpose. The analysis of normative documents regulating the amount of foam supply intensity for extinguishing high-octane gasoline was carried out in the research. The developed technique of determining foam supply critical intensity by various methods depending on the initial heating of high-octane gasoline is described, as well as the experimental installation that allows implementing a combined foam discharge method whereby foam is simultaneously discharged both onto the surface of the combustible liquid and under the layer. Methods. The authors analyzed normative documents regulating fire extinguishment of oil and petrochemicals. The study was carried out at the experimental installation developed according to the appropriate test method. Findings. The analysis of normative documents indicated differences in the criteria for choosing foam discharge intensity for high-octane gasoline. It was decided to determine the possibility of applying increasing factors for standard values of foam discharge intensity depending on time of free fire development in a high-octane gasoline tank. The experimental installation was based on the standardized installation according to GOST R 50588, which was modernized for possible foam discharge in a combined way. Fuel is preheated to determine the heating temperature effect on foam application rate. Model foam generators with a flow rate of 1.8-2.2 g/s and pans of various diameters were used to change the intensity of foam discharge. Research application field. This technique will be used for obtaining data on determining the most effective method of extinguishing high-octane gasoline at different time intervals. The experimental installation will allow obtaining new data on choosing intensity and methods of foam discharge for modern mixed gasolines. Conclusions. The carried-out work showed the relevance of conducted research work aimed at assessing the value of foam discharge critical intensity applying various methods depending on the initial heating temperature of high-octane gasoline in the tank. To determine the target value, the experimental stand and the corresponding test procedure have been developed, the results of which will be given in further publications.

Quantification of Resistivity to Determine Foam Propagation in Sandstone Reservoir

Quantification of Resistivity to Determine Foam Propagation in Sandstone Reservoir

Use of saponin foam reinforced with colloidal particles as an application to soil remediation: Experiments in a 2D tank

Foam can be used to achieve environmental remediation in case of contamination caused by light non aqueous phase spills. However, when it comes in contact with oily pollutants, foam becomes weaker and its life time is greatly reduced. Such weakening can be dampened by using silica particles -together with saponin surfactant- which were shown to reinforce foam in bulk and 1D sandpack experiments. Here is addressed both foam propagation in a 2D porous media when buoyancy and gravity interfere, and foam behaviour when in contact with floating oil. Therefore, macroscopic foam displacement, and specific liquid and gas phases behaviours were studied in a 2D-tank. A piston-like displacement was observed during foam propagation in the absence of oil, while foam liquid phase was influenced by gravity and did not propagate homogeneously on entire tank height. In the presence of oil, foam was partly destroyed, which increased the local permeability of gas and created new preferential paths for gas flow. This effect was partially avoided via a surfactant concentration increase, but solid colloidal particles turned out to be a more efficient stabilizing agent, by significantly increasing foam strength and its oil-tolerance.

Study on the regional characteristics during foam flooding by population balance model

Foam flooding is an effective method for enhancing oil recovery in high water-cut reservoirs and unconventional reservoirs. It is a dynamic process that includes foam generation and coalescence when foam flows through porous media. In this study, a foam flooding simulation model was established based on the population balance model. The stabilizing effect of the polymer and the coalescence characteristics when foam encounters oil were considered. The numerical simulation model was fitted and verified through a one-dimensional displacement experiment. The pressure difference across the sand pack in single foam flooding and polymer-enhanced foam flooding both agree well with the simulation results. Based on the numerical simulation, the foam distribution characteristics in different cases were studied. The results show that there are three zones during foam flooding: the foam growth zone, stable zone, and decay zone. These characteristics are mainly influenced by the adsorption of surfactant, the gas–liquid ratio, the injection rate, and the injection scheme. The oil recovery of polymer-enhanced foam flooding is estimated to be 5.85% more than that of single foam flooding. Moreover, the growth zone and decay zone in three dimensions are considerably wider than in the one-dimensional model. In addition, the slug volume influences the oil recovery the most in the foam enhanced foam flooding, followed by the oil viscosity and gas-liquid ratio. The established model can describe the dynamic change process of foam, and can thus track the foam distribution underground and aid in optimization of the injection strategies during foam flooding.

Generation of aqueous foams and fiber foams in a stirred tank

Generation of fiber foams with surface aeration was studied by simultaneous mixing of pulp fibers, surfactant, air and water in a lab-scale tank. The mixing took place in either transient or turbulent conditions. The effect of impeller type (RT-6 and BT-6), mixing speed, mixing power, and surfactant dosage on air content, bubble size and half-life time of the foam was investigated. Air content increased with increasing agitation power saturating to 50–75% depending on the SDS dosage. The dependence of bubble size on power was a power law with an exponent typical for processes where coalescence plays an important role. The relation between the half-life time and air content was well described by a power law. Power number of the BT-6 impeller was almost constant, and similar to that of pure water in turbulent conditions. The power number of the RT-6 impeller varied and was similarly to gas-liquid stirred tanks, in many cases clearly below that of water. The variability of the power number of RT-6 could be explained with the variation of the mixing Reynolds number.

Fire safety in tanks of oil and oil products storage

Formulation of the problem. The design of tank farms, providing them with fire protection and actions of fire and rescue units during fires or emergencies at such facilities are regulated by a number of regulations, despite the strict fire safety measures at these facilities, the number of fires in the parks storage of oil and oil products has remained unchanged for the last decades. Purpose of the article – is to develop on the basis of modernization of the existing system of fire protection of tank farms a methodology of automated water supply system for cooling tanks and formation of a fire-resistant self-tightening film for fire extinguishing with the help of a foam generator. Conclusion. The proposed sublayer fire extinguishing system provides rapid fire extinguishing by forming a fire-resistant self-tightening film on the surface of the oil product by floating in the upper part of small bubbles of low-density foam, blocking the access of oxygen to the combustion zone. The use of permanently installed in the upper belt of the tank pipelines for intensive water cooling of its walls in the event of a fire allows you to automatically perform water cooling of the tank walls without the use of gun barrels. The application of the proposed measures for fire localization makes it possible to reduce the damage from the fire by about 30… 36% compared to the generally accepted approach. The system of fire safety of facilities with the presence of petroleum products must contain a set of measures that exclude the possibility of not exceeding the values of the permissible fire risk and aimed at preventing the danger of fire and creating conditions for its successful extinguishing.

Siegwerk and Varcotec form partnership for antimicrobial coating innovation

The key to the success of matrix acidizing in carbonate reservoirs depends on the diversion efficiency of treating fluid over the total production interval, especially for treatments on vertical wells with thick formations or horizontal wells with long and heterogeneous intervals. Foamed viscoelastic-surfactant (VES) acid combined the advantage of foam and VES can distribute acid evenly in the entire production interval. However, its diversion capability and wormhole propagation behavior has not been investigated yet. Therefore, the conventional core-flooding setup was modified by adding nitrogen source and foam generator, which was used to conduct single and parallel core-flooding acidizing experiments to investigate the effect of injection rate and initial permeability on wormhole propagation, and evaluate the diversion capability under extreme permeability contrast. Furthermore, in order to characteristic the wormhole morphology, computerized tomography (CT) scanning experiments were performed on the cores after acidizing to generate a 3D view of the wormholes inside the cores. The results of single core-flooding experiments achieved the following findings: 1. The injection rate was found to be a critical parameter in maximizing the acidizing efficiency during the foamed-VES acidizing, and the optimal acid injection rate ranges from 1 mL/min to 2 mL/min under laboratory conditions. 2. The wormhole morphology changes from conical wormhole to dominant wormhole and ramified wormhole with the increase of injection rate. 3. The initial permeability of cores hardly affects the optimal injection rate and wormhole morphology, but the pore volume to breakthrough (PVbt) decreases with the increase of the core initial permeability. 4. The foamed-VES acid has a better temporary plugging capability on the cores with high permeability due to the combined effects of foam's Jamin effect and VES self-viscosified property. The parallel core-flooding experiments show that foamed-VES acid can realize the uniform distribution of acid when the permeability contrast is about 10, and overcome the limitation of conventional VES acid. However, the foamed-VES acid will work ineffectively when the permeability contrast is greater than 20. This study deepens the understanding on the foamed-VES acidizing in carbonate reservoirs and provides fundamental for field acidizing treatment design.

A non-aqueous foam concept for improving hydrocarbon miscible flooding in low permeability oil formations

Enhanced oil recovery (EOR) from carbonate formations has been challenging due to reservoir heterogeneity, unfavorable wettability, and low permeability. Thus, the application of traditional water-based EOR methods such as micellar-polymer flood in these reservoirs has been limited. With the increasing availability of natural gas, we introduce a new foam EOR concept utilizing the raw mixture of natural gas liquids (MNGLs). This process involves the injection of a non-condensable gas (i.e., nitrogen or methane) and MNGLs with dissolved non-aqueous foam stabilizing additive to maximize oil recovery based on crude oil-MNGLs miscibility and sweep efficiency due to foam improved mobility control.The objective of this study is to evaluate the performance of this unconventional foam process to improve miscible displacement in low permeability rocks. Coreflood experiments were conducted using heterogeneous carbonate cores with sub-10-mD permeability. It was found that non-aqueous foam-assisted miscible displacement can achieve promising ultimate recovery factors while significantly reducing the amount of injected MNGLs. The overall recovery could be increased up to 18% with a foaming additive dissolved in the MNGLs slug. The measured pressure drops along the core indicate that in-situ generation of foam significantly delayed the injectant breakthrough and recovered the unswept oil much further away from the injection point.

Experimental investigation on wormhole propagation during foamed-VES acidizing

The key to the success of matrix acidizing in carbonate reservoirs depends on the diversion efficiency of treating fluid over the total production interval, especially for treatments on vertical wells with thick formations or horizontal wells with long and heterogeneous intervals. Foamed viscoelastic-surfactant (VES) acid combined the advantage of foam and VES can distribute acid evenly in the entire production interval. However, its diversion capability and wormhole propagation behavior has not been investigated yet. Therefore, the conventional core-flooding setup was modified by adding nitrogen source and foam generator, which was used to conduct single and parallel core-flooding acidizing experiments to investigate the effect of injection rate and initial permeability on wormhole propagation, and evaluate the diversion capability under extreme permeability contrast. Furthermore, in order to characteristic the wormhole morphology, computerized tomography (CT) scanning experiments were performed on the cores after acidizing to generate a 3D view of the wormholes inside the cores. The results of single core-flooding experiments achieved the following findings: 1. The injection rate was found to be a critical parameter in maximizing the acidizing efficiency during the foamed-VES acidizing, and the optimal acid injection rate ranges from 1 mL/min to 2 mL/min under laboratory conditions. 2. The wormhole morphology changes from conical wormhole to dominant wormhole and ramified wormhole with the increase of injection rate. 3. The initial permeability of cores hardly affects the optimal injection rate and wormhole morphology, but the pore volume to breakthrough (PVbt) decreases with the increase of the core initial permeability. 4. The foamed-VES acid has a better temporary plugging capability on the cores with high permeability due to the combined effects of foam's Jamin effect and VES self-viscosified property. The parallel core-flooding experiments show that foamed-VES acid can realize the uniform distribution of acid when the permeability contrast is about 10, and overcome the limitation of conventional VES acid. However, the foamed-VES acid will work ineffectively when the permeability contrast is greater than 20. This study deepens the understanding on the foamed-VES acidizing in carbonate reservoirs and provides fundamental for field acidizing treatment design.

Experimental and simulation investigations of carbon storage associated with CO2 EOR in low-permeability reservoir

CO2 based water-alternating-gas (WAG) injection and surfactant-alternating-gas (SAG) injection have shown to be two effective and practical methods to enhance oil recovery, which, also achieves carbon sequestration as well. In this study, a combination of experiment and numerical simulation was used to evaluate the performances of WAG and SAG flooding in low-permeability reservoir. Core drainage experiments were conducted, and NMR equipment was used to reveal the microscopic fluid distribution and explain the macroscale drainage results for each of the enhancing oil recovery (EOR) technique. In addition, the two EOR techniques were further evaluated in a realistic low-permeability reservoir, Yushulin oil field from Songliao Basin, China. The results show that, gas phase can lower gas-oil interfacial tension (IFT) in WAG process which contributes the oil displacement from smaller pores. Besides that, the surfactant in SAG process can also improve the oil displacement efficiency in larger pores due to the generation of foams. The optimal WAG and SAG ratios (1.25–1.5) in the realistic reservoir are all higher than the typical ratio (equal to 1) from the core experimental results and that in the most conventional oilfields due to the higher heterogeneity in low-permeability reservoir with easier gas breakthrough. Furthermore, the CO2 utilization efficiency for SAG is higher than WAG.