Foam Instability Research Articles

Surfactant viscoelasticity as a key parameter to improve supercritical CO2 foam stability/foamability and performance in porous media

The performance of supercritical carbon dioxide (scCO2) foams in aquifer remediation and Enhanced Oil Recovery is negatively affected by the foam instability at underground conditions (elevated temperatures and pressures). In search of solutions, viscoelastic surfactants are considered as potential stabilizers beyond traditional surfactants. There are limited studies on the effect of viscoelasticity on foam static and dynamic properties [1–4]. We suspect that surfactant viscoelasticity would enhance scCO2 foam performance in both bulk form and porous media.A systematic study, including surfactant rheology, foamability, stability, and foam performance in porous media, has been performed to demonstrate the impact of the viscoelasticity of different surfactant solutions on scCO2 foam performance. The experimental results indicate that surfactant viscoelasticity improves the foam stability while increasing the foamability up to an optimal point, where any further increment in viscoelasticity causes a reduction in foamability. Further, foam flooding performance was positively affected as the foamability of the surfactant solution increased. The results presented in this work advances our understanding of the viscoelasticity effect of surfactants on scCO2-foam performance in porous media and provides a path for optimization of these fluids for underground applications.

Reinstating Structural Stability of Castor Oil based Flexible Polyurethane Foam using Glycerol

AbstractUse of castor oil as a renewable polyol in the polyurethane foams has been creating an attractive research interest for many researchers since last 5 decades. In this article, we examine the structural stability of flexible polyurethane foam produced using castor oil‐glycerol blend by complete replacement of synthetic polyol. Addition of castor oil in the foaming blend as a complete substitute of synthetic polyol results in instability of foam. However, addition of glycerol as a crosslinking agent in the blend helps in overcoming this instability. Cellular morphology, segmented phase morphology and bulk properties of foams were investigated using scanning electron microscope, Fourier transform infrared spectroscopy respectively. Castor oil‐glycerol blend significantly improves the foaming process at low concentrations (till 15 wt % glycerol) whereas, at higher concentrations volumetric expanding liquid undergoes faster cross‐linking leading to retarded foam growth (above 20 wt % glycerol). Strut thickness shows a sharp decline at 25 wt % glycerol. Polymer phase morphology shows absence of H‐bonded urea resulting in discrete hard segmented morphology whereas urea domains undergo agglomeration without glycerol. Foams were also characterized for thermal and bulk mechanical properties.

Enhanced Oil Recovery Using Aqueous CO2 Foam Stabilized by Particulate Matter from Coal Combustion

Carbon dioxide (CO2) foam flooding is a promising carbon capture, utilization, and storage technology that is often used for enhanced oil recovery (EOR). However, the instability of foam and low di...

Formation of stable aqueous foams on the ethanol layer: Synergistic stabilization of fluorosurfactant and polymers

The extreme instability of aqueous foams on the ethanol layer is an important issue to consider in the application of fire-fighting foams. We attempt making stable aqueous foams on the ethanol layer by using sodium dodecyl sulfate (SDS) as the foamer, with fluorosurfactant (FC1157) and xanthan gum polymers (XG) as the stabilizing agents. The surface properties, foam stability, and fire extinguishing performance of our studied systems were investigated respectively. The results show that ethanol destroys aqueous foams by dehydration and polar ethanol has a more significant defoaming effect than non-polar heptane. XG and FC1157 can inhibit the adverse effects of ethanol on foam stability. The addition of FC1157 improves the stability of the foam films and slows down the ethanol-induced dissolution of foams. XG polymers tend to form a gel-like membrane at the foam/ethanol interface, minimizing the mass transfer between foam and ethanol. The lifetime of foam stabilized by FC1157/ XG is much longer than that of foam stabilized by FC1157 or XG alone in the presence of ethanol. Foams can go from unstable foams to foams being stabilized by both XG membrane and FC1157 synergistically. As a result, the synergism of FC1157 and XG in stabilizing foams significantly enhances the fire extinguishing performance of foam.

Colloidal gas aphron (CGA) based foam cement system

Abstract To solve the problems such as high denstiy, foam instability, low compressive strength, high porosity and poor durability associated with conventional foam cements, a novel colloidal gas aphron (CGA) based foam cement system was investigated and tested for properties. CGA is used in a base slurry as the foam component and the recipe was optimized with hollow sphere and micro-silica in terms of particle size distribution (PSD). Porosity, permeability, strength, brittleness, elasticity, free water content, foam stability and density tests on the CGA based foam cement system were carried out to evaluate the performance of the system. According to the experiment results, at the foam proportion of 10%, the cement density was reduced to 1 040 kg/m3, and stable microfoam net structure not significantly affected by high temperature and high pressure was formed in the cement system. The optimal CGA based foam cement has a free water content of 0%, porosity of 24%, permeability of 0.7×10−3 μm2, low elasticity modulus, high Poisson's ratio, and reasonable compressive strength, and is more elastic and flexible with capability to tolerate regional stresses.

The influence of gas diffusion mechanisms on foam stability for foam forming of paper products

Foam forming is an innovative process for papermaking that yields various paper products with excellent formability and porosity. The stability of the foam is a critical factor in foam forming technology. The effects of different surfactants and gases (N2 and CO2) on the ability of the foams to coalesce and the stability of the foams were studied. The properties of the liquid film were investigated via high-speed camera observation and infrared spectrum. The CO2 foam was less stable than the N2 foam under the same conditions, especially for the polyvinyl alcohol surfactant. The infrared spectra and high-speed camera observation showed that the main factor that resulted in CO2 foam instability was the bubble coalescence caused via the gas diffusion in the foam column, although the process of liquid film thinning was performed simultaneously. The greater the liquid film permeability coefficient of the foam, the easier the gas was able to spread throughout the liquid film. Foam forming technology will likely be employed in many potential pulp and papermaking mill processes.

Emulsified oil phase induced internal instability of ionic and nonionic foams revealed by coarse-grained molecular dynamics simulation

Oil phase has strong hydrophobicity and weak interface tension in the foam system, which will destroy the internal structure of foam and reduce the intrinsic stability of the foam film. Coarse-grained molecular simulation techniques were employed to investigate the effect of oil phases on the structural instabilities of two typical foam systems, i.e., ionic sodium dodecyl sulfate (SDS) and nonionic pentaethylene glycol monododecyl ether (C12E5). In both systems, the pseudo-emulsion film ruptures at a critical thickness, subsequently the oil phase enters the air-water interface subsequently. Instability mechanisms are obtained by analyzing dynamic processes of the foam systems. For the SDS foam system, an oil-bridge is formed in the foam film, which is attributed to the electrostatic repulsion between the SDS at the oil-water interface and that at the air-water interface, as well as the discontinuous distribution of SDS at the air-water interface caused by the structural reversal of SDS molecules. However, for the C12E5 foam system, oil phase spreads at the air-water interfaces, which is caused by the continuous distribution of the C12E5 molecules at the air-water interface and the attractive interaction between the neutral C12E5 molecules at the air-water interface and that at the oil-water interface. The outcomes of this work shed light on the destructive mechanism of foam films induced by oil phase and provide guidelines for the design of novel oil-resistant foam system.

An exploratory study for the technological classification of egg white powders based on infrared spectroscopy

This work aims at the evaluation of FT-NIR and FT-IR spectroscopy as rapid, easy, and cost-effective tools for the classification of egg white powder (EWP) based on its technological properties. Up to 100 commercial spray-dried EWP samples with known gelling and foaming properties were used to acquire FT-NIR and FT-IR spectra. An appropriate data-splitting algorithm (Duplex) was applied in order to create, for each dataset, a calibration set and a representative validation test set for prediction. Different spectral pre-treatments and their combinations were investigated for the calculation of Partial Least Squares–Discriminant Analysis models in order to classify samples according to gel strength, foam height, and foam instability. A variable selection strategy based on the so-called Variable Importance in Projection scores was also evaluated. Both FT-NIR and FT-IR spectroscopy showed good potential in discriminating EWP samples with different technological properties. Correct classification percentages in prediction ranging from 59% to 89% were obtained with the best models calculated with selected wavenumbers. These results show a promising industrial perspective, demonstrating the possibility of developing cheap and fast instruments spanning a limited spectral range, which can be implemented on the production lines for EWP sorting and quality control.

Characteristics and functional mechanisms of clay-cement stabilized three-phase nitrogen foam for heavy oil reservoir

The large-scale application of two-phase foam flooding in heavy oil reservoirs was restricted due to the instability of foam itself. However, the developed clay-cement three-phase nitrogen foam can make up for the short broad effectively, which benefits from very good thermal stability, salt resistance, oil sensitivity and excellent plugging performance. In this paper, 8.0 wt% clay, 0.50 wt% cement particles and 1.0 wt% foaming agent were used to generate clay-cement nitrogen foam. The synergistic effects of clay/cement reaction products, particle adsorption layer and steric network contribute to a desirable protective sheath covered compact three-phase foam system with high stability and strength, the half-life of which was 42.0 min at 95 °C. Moreover, it became more stable when formation sands exist. Generally, clay-cement three-phase nitrogen foam has three kinds of plugging form owing to different formation permeability. In less permeable formations, most foam would separate into two parts, with particles stacking at the entry end and two-phase foam moving forward. While in formations with higher permeability, all foam would flow out directly without effective plugging. Only when it comes to the formations with proper permeability can this foam achieve impressive plugging strength under the effects of Jamin and particle plugging. In addition, the foaming formula can be modified by adjusting particle-surfactant concentrations to fit various formations. Therefore, it is a promising and widely applicable water shutoff agent for heavy oil reservoirs.

Effects of silica nanoparticles and polymers on foam stability with sodium dodecylbenzene sulfonate in water–liquid paraffin oil emulsions at high temperatures

The foam stability of oil–water emulsions stabilised by various surface-active components at high temperature is one of the major problems facing foam-flooding petroleum recovery because of foam instability at the high temperature underground. In this paper, foams stabilised by sodium dodecylbenzene sulfonate (SDBS), polyethylene glycol (PEG) and silica (SiO2) nanoparticles in water–liquid paraffin (50%/50%) emulsions at temperature from 20 to 80°C were studied. Foam properties such as foam stability over time at different temperatures, equilibrium surface tension, and bubble morphology (bubble size) were determined by surface tension measurements and inverted fluorescence microscopy. High foam stability was demonstrated by emulsions of SDBS, PEG, SiO2 nanoparticles, and liquid paraffin from 40 to 80°C. The properties of the PEG–SDBS foams improved when SiO2 nanoparticles were added. Foam stability increased when SDBS was adsorbed on the bubble surface as the bubbles did not rupture easily in the liquid phase in the presence of SDBS because of the formation of closely packed small bubble droplets bridging between neighbouring large bubbles, which were separated by long chain polymers. This phenomenon may arise because the SiO2 nanoparticles formed networks and were adsorbed with surfactant molecules on the bubble surface of the oil–water emulsion, causing the foam inflexibility to increase and thus improving aqueous foam stability at high temperature.

Relationship between bulk foam stability, surfactant formulation and oil displacement efficiency in porous media

Success of foam as a displacing fluid in porous media depends on longevity of foams in the presence of non-aqueous phase liquids such as hydrocarbons. The stability of foam at bulk scale has been used in many cases to screen potential surfactants for core flooding studies. Although this method may aid in determining the foamability and stability of a surfactant, no reliable correlation has been found to exist between bulk foam stability and performance in porous media. We have conducted a comprehensive series of experiments to examine and compare the stability of selected surfactant foams at bulk scale and during oil displacement in porous media. The oil displacement was investigated in a micromodel manufactured by 3D printing technology. Our results demonstrated that oil displacement efficiency by foam is strongly influenced by the surfactant formulation. More importantly, no meaningful correlation between the bulk foam stability and the oil displacement efficiency of the corresponding foams in porous media was observed. Our pore-scale investigation shows that the stability or instability of foam at bulk scale does not necessarily determine its effectiveness in porous media. Hence, performing displacement tests as presented in our study may give more insights into the potential performance of foams.

Nanoparticle‐Stabilized Foam for Effective Displacement in Porous Media and Enhanced Oil Recovery

AbstractFoam flooding is a promising technique for enhancing oil recovery, but the foam instability limits its application. This study investigates the properties of foam stabilized by silica (SiO2) nanoparticles combined with hexylamine. Surface dilational rheology, contact angle, and adsorption measurements have been performed and correlated with the foam stability. The results show that the SiO2/hexylamine dispersion induces a synergistic effect on the foam stability at intermediate hexylamine concentrations. The most stable foam was obtained with the most hydrophobic particles. The dilational viscoelasticity and the adsorption amount followed the same trend as that of foam stability. As a plugging agent, the SiO2/hexylamine foam could block the core with the maximum pressure peak at approximately 0.85 MPa. Moreover, our results indicate that the foam stability, dilational viscoelasticity, and roughness of the bubble surface together might contribute to better plugging performance in porous media.

A novel method based on ultrastable foam and improved gelcasting for fabricating porous mullite ceramics with thermal insulation–mechanical property trade-off

Foam instability and long drying cycle limits the widespread use of foaming method. In this paper, a kind of porous mullite ceramic with thermal insulation–mechanical property trade-off were fabricated via novel ultrastable foam and improved gelcasting procedure. The solidification process and stability of foam slurry, as well as the thermal, mechanical property and pore structure of the porous mullite ceramics were investigated. The results showed that porous mullite ceramics with different bulk densities could be prepared via varying volume of foam which was stable enough to be maintained in slurry for a long time. The accelerated gelation rate as well as the gelation degree resulted in the improved gelcasting method led to a shortened period of drying and demould. The obtained pores, which were small, smooth, and unimodal distributed in size in porous mullite ceramics, contributed to achieving the trade-off between thermal insulation and mechanical property.

EXPERIMENTAL INVESTIGATION OF PHYSICAL AND CHEMICAL PROPERTIES OF DRILLING FOAM AND INCREASING ITS STABILITY

This investigation presents the effect of various parameters on foam stability and its rheological properties. The underlying idea of this experiment is generating of drilling foam with uniform bubbles. The main problem of foam using is controlling its stability during field application. The most important parameters which cause Instability in foam are gravity drainage, gas diffusion and bubble coalescence. Among these parameters gravity drainage has the highest effect on foam instability in field application. For measuring of drainage effect it is necessary to produce foam with uniform bubbles.�This Experiment was performed with a specific foaming system which constructed in Research Institute of Petroleum Industry (RIPI) just for this point. This foam system consisted of an apparatus which injected nitrogen gas through a porous plate into the foam solution.In each test one parameter was variable and the effect of this variation was measured on foam properties. The main parameters which investigated in this experiment were temperature, foamer concentration, pH effect, stabilizers, and contaminants. Obtained results from testing of each parameter can be used simultaneously to improve the foam stability in elevated temperature. In this way by changing of physical and chemical properties of foam, it becomes more stable in real condition of wellbore.

Shrinkage behavior of structural foam lightweight concrete containing glycol compounds and fly ash

Shrinkage behavior of the structural foam lightweight concrete with density of 1600 kg/m 3 was investigated. Owing to high drying shrinkage of the lightweight concrete, glycol compounds were used in the concrete mixture to study their effect on shrinkage behavior. Propylene glycol (PG), triethylene glycol (TEG) and dipropylene glycol tert-butyl ether (DPTE) were selected for testing of drying shrinkage of the lightweight concrete. Partial replacement of cement and sand with fly ash was also used to reduce the shrinkage. Results indicated that PG, TEG and DPTE were effective in reducing the shrinkage of lightweight concrete through reduction of surface tension of water. However, DPTE significantly reduced the surface tension and caused the foam instability and early stiffening of mixture. The partial replacement of cement and sand with fly ash could also reduce the shrinkage of the lightweight concrete. In this case, the compressive strength was also enhanced owing to the additional pozzolanic reaction.

Analyzing Foam Instability in Commercial Beers

The foam stability of beer is impacted by positive and negative forces that counteract each other. A series of beers was investigated to assess whether foam performance was primarily impacted by the level of foam-promoting polypeptide or by the presence of inhibitory lipids. The studies involved ultrafiltration of beers and comparison of the foam stability of a standard protein (egg albumin) when foamed in the ultrafiltrates, the retentate, a reference alcohol solution, and the native beer. In all cases, the foam stability of the beers was boosted by adding protein, and there was also evidence of foam-inhibitory material in both the low and high molecular weight fractions. Hydrolysis studies with papain generated some evidence that there may be low molecular weight peptide material that is foam negative. Experiments in which beers and ultrafiltration fractions were treated with an immobilized lipid-binding protein confirmed there are foam-damaging lipids in both the high and low molecular weight fractions from beer. Improved foam performance of commercial beers demands attention both to boosting foam-promoting polypeptide levels and to attending to lipids and lipid oxidation throughout the process.

The Formability of Aluminum Foam Sandwiches: Experimental and FEM Analysis

This work deals with the formability of metal foams and it is focused on three point bending of aluminum foam sandwich panels. In this study bending can be considered as both a process for shaping of foamed panels and a mean for metal foam testing. Several tests were carried out by varying bending conditions and collecting load-displacement data. Specimens showed an interesting behaviour during bending since the sample deformation was related to the occurrence of foam cells failure or collapse. Moreover, once the process is terminated specimens retained a significant bending strength. During the experimental campaign several samples showed irregular fracture behaviour. In these cases cells fracture often starts in a generic part of the specimen (in correspondence of some non-eligible material defects) and propagates through the foam. The reasons of this problem and the possibility of failure prediction were investigated using different approaches. In particular, thickness measurements (using a ultrasound feeler) and X-ray analysis were carried out for this purpose. In addition, a study based on foam density showed a remarkable data scatter that can be considered as a characteristic of the state of the art in foamed panels manufacturing (in terms of process control and product variability). Finally, load-stroke curves were taken into account for this purpose. Computer simulations of the experiments were performed using the commercial FEM code (Deform 2D). Foam compressibility was simulated using a porous material model and the onset of foam instability was simulated by means of a specific damage criterion. Good agreement between simulative and experimental results was found.

Fragmentation of liquid and liquid-plastic media under unsteady strains

Based on a qualitative analysis of results of experimental studies, the main mechanisms of fragmentation of polar liquids and liquid-plastic media under dynamic loading are determined. In the case of low-viscosity liquids, such mechanisms are thermodynamic instability of foam, hydrodynamic instability of initial disturbances of the free surface, and the action of capillary forces. In the case of a polar high-viscosity liquid, the main mechanisms are shear instability of the structure, responsible for stratification of the medium along the lines of local failure of structural viscosity, and the action of capillary forces. The main mechanisms acting in liquid-plastic structured media (gels) are “spalling” in the zone of tensile stresses if the time of their formation is smaller than the time needed for the gel to transform to the sol state, as well as thermodynamic instability of foam and the action of capillary forces after the medium transition to the sol state.

Stabilization of Foams with Inorganic Colloidal Particles

Wet foams are used in many important technologies either as end or intermediate products. However, the thermodynamic instability of wet foams leads to undesired bubble coarsening over time. Foam stability can be drastically improved by using particles instead of surfactants as foam stabilizers, since particles tend to adsorb irreversibly at the air-water interface. Recently, we presented a novel method for the preparation of high-volume particle-stabilized foams which show neither bubble growth nor drainage over more than 4 days. The method is based on the in-situ hydrophobization of initially hydrophilic particles to enable their adsorption on the surface of air bubbles. In-situ hydrophobization is accomplished through the adsorption of short-chain amphiphiles on the particle surface. In this work, we illustrate how this novel method can be applied to particles with various surface chemistries. For that purpose, the functional group of the amphiphilic molecule was tailored according to the surface chemistry of the particles to be used as foam stabilizers. Short-chain carboxylic acids, alkyl gallates, and alkylamines were shown to be appropriate amphiphiles to in-situ hydrophobize the surface of different inorganic particles. Ultrastable wet foams of various chemical compositions were prepared using these amphiphiles. The simplicity and versatility of this approach is expected to aid the formulation of stable wet foams for a variety of applications in materials manufacturing, food, cosmetics, and oil recovery, among others.

Relations between physicochemical properties and instability of decontamination foams

The addition of dodecanol as a co-surfactant in sodium dodecyl sulfate (SDS) solution is known to stabilize the foam. This paper presents complementary studies of this system: foam liquid fraction and wall-film thickness, viscoelastic and Plateau border pressure drop measurements for foams stabilized by SDS, SDS + dodecanol and SDS + dodecanol + xanthan gum in free drainage. It shows out that the addition of dodecanol and xanthan gum in a SDS foaming solution causes not only a deceleration of the foam drainage, but of the wall-film drainage also. In a second study, results are presented for nuclear decontamination foams stabilized by alkyl polyglucosides. Preliminary results are given for co-surfactant research with the influence of the addition of decanol and dodecanol in the alkyl polyglucoside solution and the foam stabilization effect of the addition of xanthan gum is pointed out.