Foam System Research Articles

Probing the role of associative polymer on scCO2-Foam strength and rheology enhancement in bulk and porous media for improving oil displacement efficiency

Foam mobility control technique has been extensively applied to encounter unfavorable sweep efficiency during CO2 injection in heterogeneous reservoirs. Harsh reservoir conditions have encouraged a need of effective mobility control agent. In this study, we present a comprehensive experimental investigation utilizing a newly developed water-soluble associative polymer as additive to foam system for stability and rheology enhancement. The performance of polymer enhanced foam on residual oil displacement was also evaluated in porous media. A significant increment in foam longevity and improved foam rheological behavior were obtained with associative polymer presence. Compared to conventional polymer’s performance, the associative polymer enhanced foam could establish the higher flow resistance and better compatibility with reservoir conditions. The addition of associative polymer profoundly increased the foam apparent viscosity and gas mobility reduction factor at optimum foam quality in the absence and presence of oil. A noticeable improvement in oil recovery efficiency was also observed in the case with associative polymer by which 28% incremental oil recovery was achieved, 14% higher than that obtained from polymer-free foam injection. The utilization of associative polymer enhanced foam is considered promising for a deepers foam propagation in the formation to recover substantial amount of residual oil.

Application of orthogonal experiment method in foam flooding system composition and injection parameter optimization

Excellent composition and injection parameters of foam system are essential for foam flooding to exert mobility control. This study aims to optimize foam composition and injection parameters to maximize foam mobility control. The concentrations of foaming agent and stabilizer, oil saturation, foam quality, and flow rate served as influencing factors in the orthogonal experiment method with resistance factor (RF) as the evaluation index. Results showed that cores with different permeability levels corresponded to a set of optimal injection parameters. The optimal combination scheme significantly improved mobility control relative to all test groups in the orthogonal experiment, proving the effectiveness of this method in optimizing foam flooding parameters. During the analysis of orthogonal experimental data, in addition to the method of intuitive analysis was adopted to study the influence of a single factor on the RF, the influence of multiple factors interaction on the RF was also explored. Confirmatory tests were performed on the optimal parameters of foam flooding obtained by orthogonal experiments, and the foam propagation at different positions of the core was determined. The degree of pressure fluctuation during foam flooding was measured with the standard deviation ( SD ), which was used to directly measure the strength of the Jamin effect during foam flooding. The RF distribution factor ( D RF ) was introduced to describe the uniformity of foam seepage resistance along the core axis. D RF was used to study the entrance effect on foam to establish seepage resistance. The propagation performance of foam in porous medium is crucial to maximize its mobility control. Foam injectivity in porous medium should be given attention when optimizing the injection parameters of foam flooding. • Optimal injection parameters of foam are studied by orthogonal experiment method. • Obtained the influence trend of five factors on RF under various permeability levels. • Obtained multi-factors interaction effect on RF under various permeability levels. • Introduce SD and D RF to study the propagation characteristics of foam in cores.

Study of nano-SiO2 reinforced CO2 foam for anti-gas channeling with a high temperature and high salinity reservoir

CO2 flooding has been widely applied in lots of low permeability reservoirs. After extensive CO2 injection, some reservoirs began to show serious gas channeling problems. CO2 foam had been successfully used to solve gas channeling problems due to its advantages of water selective plugging features (not plugging oil). In this paper, a novel CO2 foam system was developed for high temperature and high salinity(HTHS) (85℃, 60,000mg/L) aiming at solving the gas channeling in Changqing Oilfield. Taking the foam half-life as the evaluation standard, the optimum foam system (0.5wt% EC-1+1wt% SiO2) for the target reservoir was determined. The influences of temperature, salinity and pressure on the CO2 foam performance were studied by high temperature and high pressure(HTHP)method. The ability and mechanism of anti-gas channeling were studied by experiments of sand packed tube and microscopic displacement, respectively. The results showed that the foam system possessed good foam properties at HTHS with pressure. As the concentration of SiO2 nanoparticles increased, the resistance factor of the foam system increased. However, temperature showed an adverse effect on foam stability, the resistance factor decreased with the increase of temperature. The Jamin superposition and emulsion plugging mechanism of foam system was revealed by microscopic displacement experiments.

A New Effective Multiwalled Carbon Nanotube-Foam System for Mobility Control

SummaryNanoparticles have improved a surfactant's ability to create long-lasting foam. Recent studies have widely recommended the use of silica nanoparticles to enhance foam stability. This paper presents an experimental investigation of a new and highly effective alpha olefin sulfonate (AOS)–multiwalled carbon nanotube (MWCNT) system for mobility control during gas enhanced oil recovery (EOR) operations.The new AOS–MWCNT system was evaluated for its foam stability at 150°F using a high-pressure view cell. The MWCNT was obtained as solid particles of aspect ratio up to 100 and silica nanoparticles of median size of 118 nm. The foam system was optimized for its maximum half-life by varying the concentration of the AOS and the nanotube from 0.2 to 1% and 250 to 1,000 ppm, respectively. Compatibility testing with salts was done as well. Coreflood experiments with 1.5-in.-diameter, 6-in.-long Berea sandstone cores were run to calculate the mobility reduction factor at 150°F. Nitrogen foam was injected into the core at 80% foam quality in the tertiary recovery mode, and the pressure drop across the core was measured. The formation brine had a salinity of 5 wt% sodium chloride (NaCl), and the foaming solutions were prepared with 2 wt% NaCl.The optimal concentrations of the AOS solution and the nanotubes for maximum foam stability were determined to be 0.5% and 500 ppm, respectively. The optimized AOS–MWCNT system yielded 60% greater nitrogen foam half-life (32 minutes) than an optimized AOS–silica system at 150°F. The foam half-life of a stand-alone 0.5% AOS solution was 7 minutes. In the presence of crude oil, the foam half-life decreased for all the tested systems. Coreflood experiments at 150°F showed a significant increase in the mobility reduction factor when the new AOS–MWCNT system was used as the foamer instead of stand-alone AOS or AOS–silica system. The new foaming system was stable through the duration of the experiment, yielding foam in the effluent samples. There was no formation damage observed. Salt tolerance for the MWCNT nanofluid was higher than the silica nanofluid.Foam needs to be stable for long periods of time to ensure effective mobility control during gas injection for EOR. This paper investigates a new highly effective AOS-multiwalled carbon nanotube system that outperforms the AOS–silica foaming systems in terms of foam stability and mobility control at 150°F.

Investigation of the Blocking Effect of Foam with and without Nanoparticles in Cores with Different Permeabilities

The blocking characteristics of two foam systems, the surfactant foam and the surfactant-nanoparticle (NP) foam, were compared. In bulk foam experiments, the drainage half-life and the foam morphol...

Особенности теплозащитных свойств пенообразующих систем при ликвидации пожаров на танкерах

The article considers means of fighting fires on tankers carrying oil products. The foam hydro monitors are considered the effective means for fighting a fire on tankers, their positive and negative sides are described after using on the merchant ships. A number of experiments have been carried out to obtain adequate models of the heat-shielding properties of foamed films. Investigations on modern foam-forming systems, which are actively used on ships carrying oil products during fire extinguishing are presented. The criteria have been analyzed that should be taken into account to obtain a model of the heat-shielding action of foaming agents. A model of heat protective effect of foaming agents has been modeled. Sodium silicate was chosen as the main foaming element. After using sodium silicate in different concentrations, it was combined with different samples of seawater (from the Dead Sea, the Black Sea and the Mediterranean Sea). When mixing a foaming agent with a mass content of 2.5% with water from the Black and Mediterranean Seas, the volume of the obtained foam makes less than 30%. It has been inferred that using seawater as a foaming catalyst for binary foaming systems is available. There was conducted an experiment for determination of corrosion which was carried out using fragments of the walls of tanks made of steel grade Ст 3 with 5 mm thick. There has been defined the average rate of weight loss per unit area of metal plates when they are exposed in the investigated aqueous solution. There has been substantiated availability of using sea water as a foam catalyst for binary foam-forming systems.

Hygrothermal performance of six insulation systems for internal retrofitting solid masonry walls

The study investigated the hygrothermal performance and risk of fungal growth in a phenolic foam system with a closed cell structure and a diffusion-open and capillary active lime-cork based insulating plaster, for internal retrofitting purposes. The setup comprised two 40-feet (12.2 m) insulated reefer container with controlled indoor climate, reconfigured with 24 holes (1 × 2 m each) containing solid masonry walls with embedded wooden elements on the interior side. Focus was on the conditions in the masonry/insulation interface and embedded wooden elements, and the performance of the two systems were compared to three diffusion-open insulation systems and one diffusion-tight. The effect of exterior hydrophobisation was also investigated. Relative humidity and temperature were measured in several locations in the test walls over 2½ years, and the risk of fungal growth was evaluated by on-site measurements and the VTT mould-growth model. The findings indicate that internally insulated walls with bare brick exterior surfaces performed poorly with high risk of fungal growth. The effect of exterior hydrophobisation was found to vary with the orientation and the installed insulation system, with a generally positive effect on walls facing south-west but limited effect for north-east. Furthermore, the more diffusion-tight insulation systems were found to perform better in combination with exterior hydrophobisation than the highly diffusion-open systems. The lime-cork insulating plaster showed high relative humidity and risk of moisture-induced problems. The on-site fungal tests showed no growth in the masonry/insulation interface inside the two insulation systems, probably due to high initial pH-value.

Effect of homogenisation in foam and emulsion mix beverage colloidal system: A case in Teh Tarik

Teh Tarik is a frothed milk tea consisting of Ceylon Tea, condensed milk, sugar, where it is traditionally prepared by pulling motion to get aerated. High-shear homogenisation through rotor-stator homogeniser was explored in this study as an alternative method to produce Teh Tarik at a larger scale and at the same time enhancing the stability of the Teh Tarik emulsion and foam. Varying speeds (11,000 rpm, 18,000 rpm and 25,000 rpm) of homogenisation resulted in size reduction of milk fat globules to various degrees. This reduction in particle size by at least 0.4 μm consequently increased the stability of the milk tea emulsion, which is the most significant (α = 0.05) at the speed of 18,000 rpm. At the same time, increasing speed of homogenisation from 11,000 rpm to 18,000 rpm and 25,000 rpm also reduces dynamic surface tension through the increased protein adsorption rate at the water-air interphase and ultimately reducing foam drainage. Subsequently, the improved physical stability of emulsion and foam could be made use to develop satiety- and satiation-enhanced beverage as a modus operandi to reduce calorie intake among Malaysians.

Surface Dilatational Properties and Foam Performance of Surfactant-Nanoparticle Foaming System under Ultra-High Salinity

Abstract We have studied the surface dilatational properties of aqueous foaming dispersions containing mixtures of silica nanoparticles (Ludox CL) and sulfobetaine (LHSB) in Tahe formation water. The effects of temperature and pH on the surface dilatational modulus and time shift were studied by oscillating drop module (ODM). The ODM results show that the surface dilatational modulus of mixtures of CL and LHSB is large and increases with the decrease of surface area deformation, which results from hydrophobic interaction between adsorbed mixtures. Under test conditions, the Gibbs stability criterion E > σ/2 against foam coarsening is fulfilled. Results of Brewster angle microscopy (BAM) show that an uniform adsorption layer is established at the air-water interface. Temperature and pH-value influence the dilatation modulus of the surface by hydrophobic interaction or adsorption. Time shift has a similar variation trend. This is a surprising feature. It suggests that LHSB adsorbed on CL can respond to surface tension gradient. The time shift difference results from the response of LHSB at different adsorption sites. In addition, sand pack tests show that compared to LHSB, a finer foam was produced by the mixtures CL/LHSB due to the capillary-induced \snap-off". Thus, higher pressure difference and higher oil recovery could be achieved.

SHAPE MEMORY POLYMER HYDROGEL FOAMS FOR FISTULA CLOSURE

Abstract Introduction Crohn’s disease can lead to fistula formation between portions of the urinary, reproductive, and digestive systems. The abnormal connections caused by these tunneling sores cause severe pain, infections, and abscess formation. Currently, 83% of Crohn’s patients with fistula formation undergo surgical intervention to either drain or bypass the fistula openings, and ~23% of these patients ultimately require bowel resections. To address this clinical need, we propose to synthesize a shape memory polymer (SMP) hydrogel foam system for fistula closure and healing. SMP foams are porous materials that can be heated and compressed into a low-profile geometry that is retained after cooling. This shape enables minimally invasive delivery (i.e. via catheter) to a fistula site. Once the foams are heated to body temperature, they expand back to their original shape to conform to the implantation site geometry. Here, we present a degradable SMP hydrogel foam with antimicrobial and antioxidant phenolic acids for potential use as a fistula closure scaffold. Methods Foams were synthesized with 3-arm and linear poly(ethylene glycol) (PEG), amylopectin/pullulan, and phenolic acids in combination with hexamethylene diisocyanate in the presence of surfactants, catalysts, and foam blowing agents to form a hydrophilic, chemically crosslinked foam. Resulting foams were characterized in terms of swelling ratios, pore sizes, glass transition temperatures, and shape recovery. Degradation profiles were characterized in glucoamylase. Antimicrobial efficacy against E. coli was measured by quantifying colony forming units of bacteria following exposure to SMP hydrogels. Antioxidant properties were assessed in the presence of hydrogen peroxide. Results SMP hydrogel swelling ratio, stiffness, shape memory properties are tuned by altering monomer ratios and lengths and foaming conditions. In preliminary degradation studies in glucoamylase, degradation rates are dependent upon starch content; increased degradation is observe with increase pullalan content, Figure 1. Phenolic acid-containing SMP foams exhibit antimicrobial efficacy against E. coli and antioxidant properties in hydrogen peroxide. Conclusions Current studies include full material characterization of the library of synthesized hydrogels and longer-term degradation analysis. This system can be further built upon in future studies to include a drug-delivery component. Overall, SMP hydrogel foams present a highly tunable platform material that can be modified with required functionalities to promote fistula closure.

In situ synthesis of CO2 adducts of modified polyethylenimines in polyether polyols for polyurethane foaming

CO2 adducts from hydrophobically-modified polyethylenimines (PEIs) in powder form are newly-developed environment-friendly blowing agents for polyurethanes (PUs). However, they are difficult to disperse into foaming systems that usually contain polyether polyols as the PU soft segments. Herein, we employ mixtures of di(propylene glycol) monomethyl ether-grafted polyethylenimines (DPG-PEIs) and poly(propylene glycol) (PPG) polyols to absorb CO2, with in situ formation of the CO2 adduct particles as PU blowing agents. Their CO2 saturation degrees, revealed by thermogravimetry, scatter in the range of 93–98%. The DPG side chains tend to be exposed at the particle–matrix interface to stabilize the particles. In addition, some PPG oligomers in the matrix might entangle with the CO2 adduct macromolecules during the in situ particle formation. The entangled PPG chains could further stabilize the suspending particles. The high grafting rate and high molecular weight of the PEI backbones could result in small particles, which largely thicken the foaming systems. The optimized blowing agents, with grafting rates between 5% and 8% and PEI backbone molecular weights not higher than 10k Da, show particle sizes from several hundreds of nanometers to ∼1 μm. The resultant foams demonstrate densities below 50 kg/m3 and compressive strengths over 200 kPa, comparable to the values from industrial foams. This in situ CO2 adduction has potential as a universal method suitable for PU foaming at an industrial scale.

Study on the interfacial thermal conductance between metals and phase change materials

Foam metal phase change composite materials and systems play a crucial role in the heat (cold) storage system. The interfacial thermal conductancebetween different foam metals and phase change materials under different phases isan important factor to affect the heat (cold) storage process of theheat (cold)storagesystem. In this paper, the interfacial thermal conductancebetween the three metals(copper, aluminum and nickel) andtwo phase change materials (paraffin and erythritol) in solid and liquidis measured by time-domain thermoreflectanctechnique. The experiments suggest that regardless of the types (paraffin or erythritol) and phases (solid or liquid) of phase change materials, the interfacial thermal conductance results preserve the same trend that copper < nickel < aluminum. By performing a series of molecular dynamics simulations and phonon-level analyses, the mechanisms for the above trend are identified to be the dominant contribution of lattice vibration in z direction and mismatching degrees of metal/phase change material interfaces. The interfacial thermal conductance of metals/paraffin are bigger than metals/erythritol in the same conditions.Compared with solid state, two kinds of phase change materials in liquid state show biggerinterfacialthermal conductance for all kinds of metals.

Modification and Properties of EVA Foamed Material with Hemp Stem Powder

In this study, a certain amount of hemp stem powder was added into ethylene-vinyl acetate (EVA) copolymer foam system by molding, and the improvement of properties of composite foam system with different hemp stem powder content of 0-30% was studied. The results showed that hemp could decrease the hardness and density of the composite foam system, improve the resilience and compression deformation rate, and have excellent moisture absorption and quick drying properties and antibacterial properties. The results show that the foaming system with 10% - 20% hemp stem powder has the best comprehensive mechanical properties, which can be used in shoes.

Intensification of the Foam Technology by the Energy of Electrohydrothermal Force Fields. Part 3. Investigation of the Processes of Heat and Mass Transfer in a Foam System under the Action of EHTFF

As a result of thermal expansion of the gas phase of a foam mass playing the role of compacting component in a closed volume, we observe the appearance of excess internal pressure accompanied by the formation of the fields of pressure, temperature, and moisture content. The partial flows of liquid caused by these fields are directed from the center toward the perforated walls of the form and go further leaving the form. Under the action of electrohydrothermal force fields, we observe the appearance of three partial flows of moisture combined into a single flow in the mass. Thus, the phenomenon of self-compaction is accompanied by the processes of heat and mass transfer. At low temperatures, moisture moves in the material in the form of a fluid. At the same time, at high temperatures, it has the form of vapor. The density of the total flow of moisture can be represented as the sum of densities of the partial flows. The analytic investigation of the mechanism of heat-and-mass transfer flows enables us to study the behavior of the foam mass in the course of heat-and-force treatment and to choose the best conditions for this treatment.

FORCED CONVECTION COOLIG OF MULTIPLE HEAT SOURCES USING OPEN CELL METAL FOAMS

A numerical simulation is performed for heat transfer enhancement in a parallel-plate heat exchanger equipped with multiple metal foam blocks of various size. Localized heat sources are placed on the top wall of the exchanger in the location of the metallic foam blocks. The Brinkman-Forchheimer-extended Darcy model is used to characterize the flow field inside the foam region. Solution of the coupled governing equations for the composite fluid/ foam system is obtained using the finite volume method. In this study, the influence of the parameters such as the Darcy number, the Reynolds number and the arrangement of the foam samples on the hydrodynamic and thermal behavior of the flow are deeply analyzed. The results are reported for two different configurations containing four metal foam blocks mounted alternately on the top and bottom of the channel walls: (1) blocks are attached straightly to the channel walls and (2) blocks positioned at a precise distance from the channel walls . The obtained results show that the improvement of the cooling of the heat sources by forced convection is better in configuration (2).

Effect of Biocidal Additives on Technological Parameters in the Manufacture of Polyurethane Foams

This paper presents results of investigating the effect of biocidal additives (BCAs) (tebuconazole, Polisept, Anavidine, nanosized silver particles, etc.) on technological parameters of polyurethane foam (PUF) systems based on imported and Russian-made polyesters and polyethers. The diagram of the technological process of manufacturing PUF samples is given. The microstructural and technological parameters are investigated: start time, gelation time, foam rise time, and product molding time. A comparative analysis of the properties of the manufactured PUF samples is carried out. As part of this work, tebuconazole was microencapsulated using polymer systems based on an epoxy core and urea-formaldehyde resin. The manufacturing process is described, and the structural parameters of microcapsules are investigated. The maximum permissible concentrations of the studied BCAs were determined, the excess of which led to significant changes in the structural and technological parameters of the samples of model PUF systems.

Study on the stability and rheological properties of nitrogen foam under high-pressure condition

After a period of exploitation of carbonate fractured-vuggy reservoir, the water content of oil well keeps increasing, and some wells appear violent water flooding in a short period of time, which leads to the rapid decrease of production. The injection of particle plugging agent is one of the main measures to improve the oil recovery. Foam fluid has the characteristics of low density, high viscosity and low moisture filtration, which can effectively carry plugging particles to the target plugging layers. A stable foam system with high temperature and salinity is optimized and the rheological properties of the foam are studied in this research. The results show that the foam can maintain high viscosity and carry particles effectively even at a higher shear rate.

Visualized Study of a Nanoparticle-Assisted Foam System to Enhance Oil Recovery by Nuclear Magnetic Resonance Online Flooding Experiment

To solve the problems of high water cut and low oil production in some blocks of Xinjiang Oilfield, nanoparticle-assisted foam flooding technology has been proposed recently to improve the oil recovery. In this study, the foam static evaluation experiment was first employed to study the effects of modified nano-SiO2 on foam stability and foaming performance. Then, the influences of temperature and salinity on foam stability were investigated. Finally, both the water and oil displacement performances of foam systems with and without nanoparticle assistance were studied separately by the nuclear magnetic resonance (NMR) online flooding experiment. Foam static evaluation results showed that the stability of the foam was obviously increased by modified nano-SiO2 particles. However, the foam stability slightly decreased with the increase in temperature and salinity. Moreover, the foam half-life under the reservoir conditions of 80 °C and 80,000 mg/L salinity could reach 240 min, indicating that resistance to high temperature and salinity of the nanoparticle-assisted foam system was enhanced compared to that of the conventional foam systems. Magnetic resonance imaging results demonstrated that the water displacing effect of the nanoparticle-assisted foam system was significantly increased compared with that without adding modified nano-SiO2. The core finally contained almost no original water after flooding. In addition, the nanoparticle-assisted foam system can substantially improve oil displacement efficiency and increase the oil recovery efficiency by 31.11 percentage points based on the results of water flooding.

Preparation and Insights of Smart Foams with Phototunable Foamability Based on Azobenzene-Containing Surfactants.

Smart foams with tunable foamability exhibit superb applications in many fields such as colloidal and interface science. Herein, we have synthesized an azobenzene-containing surfactant with excellent photoresponsiveness by a simple thiol-maleimide click reaction between thioglycolic acid and 4-(N-maleimide) azobenzene (MAB). The structure and the photoresponsive behavior of the novel surfactant are characterized. Depending on the solution concentration, the synthesized surfactant demonstrated various speeds for the trans/cis photoisomerization varying from 9 to 24 s for the given concentration range and excellent reversible photoisomerization cycling stability (more than 20 cycles) upon light irradiation. Based on these conformational switches, a series of phototriggered obvious surface properties (e.g., critical micelle concentration (CMC), surface tension (γ), and surface excess concentration (Γ)) changes of the surfactant are achieved. More specifically, the smart foam system with tunable foamability is realized. As-formed smart foams with rapid photocontrolled reversible foaming/defoaming transition and excellent cycling stability make them very attractive candidates for applications in wastewater treatment, green textile, oil extraction, and emulsification.

Study of the preparation and extinguishment characteristic of the novel high-water-retaining foam for controlling spontaneous combustion of coal

For enhancing the wetting effect of foam on residual coal in goaf to control spontaneous combustion of coal efficiently, this study proposed the novel high-water-retaining foam with excellent water retention and extinguishment performance. Polymer composite (PC) as thickening agent and organic boron complex (OBC) as crosslinking agent were introduced into foam system to form gel structure by borate/cis-hydroxy bonds in foam film to hold water. Preparation experiments indicated that high-water-retaining foam with the component range of 3.4 ~ 4.8 g/L PC and 2.0 ~ 3.4 g/L OBC showed the crosslinking time more than 30 min, which was conducive for foam to spread fully to cover and wet the residual coal in goaf. Considering the foam foamability and stability, this study revealed that the optimal component proportion of high-water-retaining foam was 4.0 g/L PC and 3.0 g/L OBC, exhibiting the largest foam comprehensive value of 529.82 and best foam performance. Water retention capacity of foam tests indicated that high-water-retaining foam could hold the water in foam system above 60% after placing 120 h, while traditional aqueous foam had lost 98% water. And coal-fire extinguishing tests indicated better extinguishment characteristic of high-water-retaining foam than that of traditional aqueous foam as evidenced by faster cooling and extinguishment rate to burning coal for the novel foam. Moreover, high-water-retaining foam would cover the coal fully for a long term to prevent oxygen from feeding the fire, finally controlling spontaneous combustion of coal efficiently.