Foam Drainage Research Articles

Investigation on working principle of pipe string for liquid retention and refoaming in the wellbore of natural gas well with foam drainage gas recovery

ABSTRACT The use of foam drainage gas production in natural gas wells can quickly recover the accumulated water in the wellbore, reduce the bottom hole pressure, and increase the production of gas wells.Due to the poor stability of the foam in the wellbore, the liquid phase will migrate downward along the wellbore wall after the foam is broken, reducing the efficiency of the foam drainage.In order to further improve the efficiency of foam drainage, this paper studied the retention mechanism of liquid in wellbore through numerical simulation combined with laboratory experiment, and analyzed the retention effect of different structures of relocators on reflux liquid.In addition, we designed a foaming device with a crack structure, and used the reflux liquid to foam again, so as to improve the efficiency of foam drainage and gas recovery.The results show that the wavy retaining apparatus has strong water retention capacity in the process of foam drainage and gas recovery.During the simulation time, the liquid phase volume fraction is relatively stable, remaining between 82.8% and 83.4%, indicating that there is no significant change in the liquid phase in the reentrant, which can prevent the water phase from settling to the bottom of the well.The pressure comparison of the three kinds of arrester inlet is as follows: wavy arrester < rectangular arrester < zigzag arrester.The pressure at the entrance of the wave-shaped redetention shows a fluctuating increase and remains at about 2.5–4 Pa, indicating that the flow resistance in the wave-shaped redetention is relatively low and cannot greatly increase the pipe flow resistance in the wellbore.After the high-speed airflow passed through the reentrant with water phase, dispersed bubbles were produced in combination with the secondary foaming device. The foaming effect of rectangular foaming device and pulsed trapezoidal foaming device was the best, and 8 bubble particles were produced within 500 ms.The addition of secondary retained foam structure can effectively reuse the water phase after foam breaking. The injection pressure is up to 19 mm/min at 2.5mpa, and the drainage speed is increased by 200%-240%, indicating that the foam breaking in the wellbore seriously affects the drainage efficiency. This study can effectively solve the problem of wellbore fluid accumulation in natural gas Wells, which is of great significance to the efficient development of natural gas Wells.

Soil conditioning tests on sandy soil for earth pressure balance shield tunneling and field applications

When performing earth pressure balance (EPB) shield tunneling in a sandy stratum, spewing and incomplete soil discharge often occur. Soil conditioning agents are needed to modify the excavated soil so that it has flow plasticity. Conditioned sandy soil and conditioning agents from Nanchang Metro Line 4 were evaluated using laboratory and performance tests. The results show that the foam expansion rate (FER) and half-life time (H-T) increase with increasing foam agent concentration (cf) up to a critical concentration of 5%. A high molecular weight polymer inhibits the FER and H-T of the foam. However, when the VR (the volume ratio of the polymer and foam agent) exceeds 0.3, the polymer increases the viscosity of the foam agent solution, which reduces the foam drainage rate and increases the foam stability. The reduction of the soil permeability by the polymer is the most obvious effect. When FIR = 40%, VR = 0.1 and SIR = 30%, the conditioned sand undergoes an appropriate state with good flow plasticity, with relatively low rotational torque and SD because the agglomeration effect of the polymer improves the homogeneity of the sandy soil. The engineering application of this soil conditioning scheme, which was based on laboratory test results, ensured the smooth completion of the tunnel.

The evolution and influence factors of CO2 flooding crude oil defoaming behavior after depressurization

CO2 flooding crude oil may generate abundant foams in oil field separators after depressurization. A large amount of foams occupies most of the space in a separator and spends much time to burst, which, in turn, reduces the separation efficiency of the separator. Moreover, the incomplete gas-liquid separation will cause corrosion in the downstream pipeline, and damage both the pump and the compressor. Based on the self-development crude oil depressurization foaming device and the CO2 flooding crude oil, this paper studies the evolution of foam and analyzes the function mechanism of asphaltene and wax crystal on defoaming and drainage of crude oil quantitatively. The experimental results show a law that the rate of defoaming and drainage increase at the initial stage and then decrease, which is available for different crude oils. So, the paper proposes a kinetics model of the defoaming and drainage based on the three-degree polynomial function innovatively, which not only describes the evolution of foam volume, but also indicates the change of foam drainage rate. Meanwhile, the experiments found that asphaltene promoted the stability of foams by being adsorbed on foam film in the process of liquid drainage. Wax crystal reduced the fluidity of drainage, which decreased the defoaming and discharging rate. But the wax crystal with specific structures reduced the stability of foams. It is significant to explore the foaming and defoaming mechanism of crude oil for providing references for the improvement of separator efficiency and the development of separation technology.

Thermal Stability of Gel Foams Stabilized by Xanthan Gum, Silica Nanoparticles and Surfactants.

The foams stabilized by nanoparticles (NPs), water-soluble polymers, and surfactants have potential application prospects in the development of new, environmentally friendly firefighting foams. In the present study, a gel foam containing a water-soluble polymer (xanthan gum, XG), hydrophilic silica NPs, hydrocarbon surfactant (SDS), and fluorocarbon surfactant (FS-50) were prepared. The surface activity, conductivity, viscosity, and foaming ability of foam dispersions were characterized. The gel foam stability under a radiation heat source and temperature distribution in the vertical foam layer were evaluated systematically. The results show that the addition of NPs and XG has a significant effect on the foaming ability, viscosity and foam thermal stability, but has a very subtle effect on the conductivity and surface activity. The foaming ability of the FS-50/SDS solution was enhanced by the addition of NPs, but decreased with increasing the XG concentration. The thermal stability of the foams stabilized by SDS/FS-50/NPs/XG increased with the addition of NPs and increasing XG concentration. Foam drainage and coarsening were significantly decelerated by the addition of NPs and XG. The slower foam drainage and coarsening are the main reason for the intensified foam thermal stability. The results obtained from this study can provide guidance for developing new firefighting foams.

Dynamical behaviour of the foam drainage equation

In this study, we examine the well-known foam drainage equation in the form of the nonlinear partial differential equation using a new extended direct algebraic method. This remarkable powerful method transforms the equation under study into an ordinary differential equation using a wave transformation which provides an exact form to the problem considered in the paper. Graphical representation for the acquired solution is presented through 3-D plots which variable parameters to show the efficiency and simplicity of the method used. From these plots, the methods prove to be a reliable and effective approach for solving nonlinear similar problems and can be accounted for in the near future for possible application to similar models.

Application of Foam Drainage and Gas Extraction in Gas Field Development

Application of Foam Drainage and Gas Extraction in Gas Field Development

Performance evaluation of foaming agent in high sulfur formation water environment

In order to increase gas production, the foaming agent is usually injected into the bottom of the well. This process can effectively reduce the backpressure at the bottom of the well, so as to achieve the ultimate goal of drainage gas recovery and enhanced oil recovery. Foam drainage efficiency is affected by many different factors, which makes its drainage efficiency change to a large extent. This paper has done a lot of research on the performance of foam drainage agents in high sulfur formation water environment. The foaming performance, foaming stability, liquid carrying performance, and the effect of foaming discharge agent on the COD value of formation water were experimentally studied in room temperature and high-temperature environment respectively, in order to find out the optimal parameters of foaming discharge agent performance in a high sulfur formation water environment.

Similarity solutions for early-time constant boundary flux imbibition in foams and soils

The foam drainage equation and Richards equation are transport equations for foams and soils, respectively. Each reduces to a nonlinear diffusion equation in the early stage of infiltration during which time, flow is predominantly capillary driven, hence is effectively capillary imbibition. Indeed such equations arise quite generally during imbibition processes in porous media. New early-time solutions based on the van Genuchten relative diffusivity function for soils are found and compared with the same for drainage in foams. The moisture profiles which develop when delivering a known flux into these various porous materials are sought. Solutions are found using the principle of self-similarity. Singular profiles that terminate abruptly are obtained for soils, a contrast with solutions obtained for node-dominated foam drainage which are known from the literature (the governing equation being now linear is analogous to the linear equation for heat transfer). As time evolves, the moisture that develops at the top boundary when a known flux is delivered is greater in soils than in foams and is greater still in loamy soils than in sandstones. Similarities and differences between the various solutions for nonlinear and linear diffusion are highlighted.Graphic abstract

Natural surfactant system: precursor flow in one-shot two-dimensional foam drainage.

Foam drainage, the downward flow of the intervening liquid due to gravity, surface tension and viscosity, is an important factor for foam stability. Forced drainage (adding liquid to a foam column from the top) is used to study liquid flow characteristics in foam. The different competing phenomena involved in the vertical and horizontal movement is studied by visually monitoring the draining liquid using a dye. Hence, this study is called two-dimensional (2D) drainage, horizontal movement being considered as just one dimension. We report, for the first time, 2D forced drainage in a natural surfactant extracted from Sapindus mukorossi. Draining wave front flows vertically and spreads horizontally. Vertical front position proceeds with time in a power law whose exponent indicates a Poiseuille flow, like synthetic surfactants. The wave front begins as a conic form downstream producing an expanding ellipsoid with time. The liquid fraction, taken as light intensity at any point, follows a Gaussian distribution along the horizontal. There is an asymmetric Gaussian distribution along the vertical which distorts after 10 s, indicating two types of flow occurring simultaneously. Two such liquid movements through foam have not been reported in the literature. The reason behind these two types of flow needs further investigations.

Classical solvability to the initial boundary value problem for a forced foam drainage equation

In this paper we study a nonlinear partial differential equation describing the evolution of a forced foam drainage in one dimensional case. A foam drainage equation was proposed by Goldfarb et al. [5] in 1988 in order to investigate the flow of liquid through channels (Plateau borders) and nodes (intersections of four channels) between the bubbles, driven by gravity and capillarity. Mathematical studies on a foam drainage equation so far are restricted within numerical and particular solutions; as for mathematical analysis of it there are only a few. This paper is aimed at proving that the initial boundary value problem for the forced foam drainage equation admits a unique global-in-time classical solution by the standard classical mathematical method, the maximum principle and comparison theorem. Moreover, the existence of its steady solution and its stability are shown. This is the first rigorous mathematical result for a series of researches on this equation.

Random Packing Performance in Continuous Foam Fractionation

AbstractThe #25 teller rosette (TR) random packing was used to enhance foam drainage in foam fractionation under continuous steady‐state conditions and tested using sodium dodecyl sulfate (SDS) as a model surfactant. A column without the #25 TR served as control. The results demonstrated that the #25 TR was capable of enhancing the foam drainage and enrichment ratio while reducing the liquid holdup. The experiment was set up with optimized feed flow rate, liquid pool height, air flow rate, and SDS feed concentration. The enrichment ratio obtained by the #25 TR column was 1.76 times higher compared with the control column. Based on the mass balances and equilibrium relationship, a new method for graphical illustration of theoretical stages is also presented.

Foaming and foam mat drying characteristics of ripe banana [Musa balbisiana (BB)] pulp

AbstractFoam‐mat drying characteristics of wild ripe banana [Musa balbisiana (BB)] pulp on the attributes of the product were investigated. The effects of pulp concentration (PC), skim milk powder (SMP) and whipping time (WT) on foaming characteristics such as foam density, drainage volume and foam expansion were studied. The obtained optimum condition for the foaming process was 9.62°Brix of PC, 8.18% of SMP, and 145.54 s of WT. The hot air drying of banana foam was carried out at 50–70°C; the drying rate and moisture diffusivity (3.9–5.9 × 10−10 m2/s) increased with drying temperature. The physico‐chemical properties of banana foam powder such as moisture content, water activity, bulk density, and Carr index decreased with an increase in drying temperature, whereas hygroscopicity, water solubility index, and water absorption index increased. The dried samples were moderately bright in color and had a porous microstructure. The present study is expected to be useful in the preparation of banana powder.Practical ApplicationsFoam‐mat drying technology is a pragmatic method to dry fruit juices and pulps. The concept behind the foam‐mat drying is an increase in the surface area of material to be dried. The process depends on the material property of pulp/juice and the use of the additives to create a foam structure and ensuring its stability during the phase of drying to offer granular products having low bulk density.

A combined approximation method for nonlinear foam drainage equation

The aim of this study is to develop a combined approximative technique to find a numerical solution to the foam drainage equation arising in various absorption and distillation processes. In this approach, first, the discretization of time is performed with the aid of the Taylor expansion series. Hence, a collocation method based on novel Bessel polynomials is utilized for the space variable. Thus the solution is found by solving a linear system of algebraic equations at each time step in contrast to solving a nonlinear system. Numerical simulations are provided to check the accuracy and efficiency of the presented algorithm. The numerical results are compared with exact solutions as well as with the outcomes of other existing available numerical methods.

Effect of SDS surfactant on gas-liquid flow and slug characteristics in slightly upward pipeline

A new pigging approach with SDS (Sodium dodecyl sulfate) surfactant was proposed for foam drainage in the gathering pipelines with wet gas production, especially for the pipeline section with a great pigging risk. For this purpose, the loop of gas-liquid two-phase flow with a 3 ° slightly upward pipeline was designed. The flow pattern characteristics of gas-liquid two-phase flow were collected by a high-speed camera, and the flow patterns with typical morphological structure were classified. Ultrasonic Doppler velocimeter and ultrasonic transducer were used to measure the velocity signal of the liquid phase near the pipe, and the slug frequency was calculated accurately according to the change of velocity profile data. The slug length was measured by the signal collected by pressure and differential pressure transmitter. The results show that with the addition of SDS surfactant, the flow pattern of gas-liquid two-phase flow is obviously improved, and the working condition of slug flow is suppressed. Besides, in the specific slug flow condition, the slug frequency decreases significantly and the slug length increases. It indicates that the addition of SDS surfactant is favorable to liquid discharge, and provide a reference value for the application of SDS surfactant in foam drainage in wet-gas gathering pipelines.

A study of the fractal foam drainage model in a microgravity space

The foam drainage mainly depends on the influence of gravity and foam surface tension. In this work, we consider the foam drainage in a microgravity condition, and its fractal modification is established by using the fractal derivative. The variational principle of the novel fractal model is successfully obtained by the semi‐inverse method. Finally, an analytical solution is obtained by the variational iteration method; the effect of the fractal order on the solution property is illustrated.

Foam fractionation for effective removal of Pseudomonas aeruginosa from water body: Strengthening foam drainage by artificially inducing foam evolution

Lack of microbial contamination is of great significance to drinking water safety and water reclamation. In this work, foam fractionation was employed to remove Pseudomonas aeruginosa (P. aeruginosa) from aqueous solution and dodecyl dimethyl betaine (BS12) was used as the collector. Since the attachment of strain cells on the bubble surface would impede the reflux of interstitial liquid in the plateau borders (PBs), a novel strategy in strengthening foam drainage was developed through artificially inducing foam evolution. Two gas distributors with different pore diameters had been mounted at the bottom of the column for regulating the radial distribution of bubble size in the foam phase. Experimental results indicated that gas diffuse and bubble coarsening could be significantly promoted by increasing the size difference among the adjacent bubbles. Bubble coalescence contributed to broadening the width of plateau borders, thereby avoiding the borders blockage by strain cells. During bubble coalescence, surfactant molecules would be partially shifted from the surface of small bubble towards that of large bubble due to the molecule density difference. The increase in surface excess of surfactant molecules on gas-liquid interface was conducive to improving foam stability. Under the suitable conditions of air flow rates of gas distributor with 0.125 mm of pore diameter 75 mL/min and gas distributor with 0.425 mm of pore diameter 125 mL/min, BS12 concentration 0.1 g/L, and P. aeruginosa concentration 2.0 × 104 CFU/mL, the removal percentage and enrichment ratio of P. aeruginosa were 99.6% and 10.6, respectively. This work is expected to provide some new light for strengthening foam drainage in the presence of solid particles and to facilitate the industrialization of foam fractionation in water treatment.

Fluorosurfactant retention in the foam blanket during gravitational drainage of an aqueous film-forming foam

A model aqueous film-forming foam (AFFF) comprising a fluorocarbon surfactant (6:2 FTSaB), hydrocarbon surfactant, solvent, and water was deployed on a heptane fire with the gravimetrically-drained foam solution collected at regular time intervals and analysed for surfactant concentration.Foam drainage behaviour within the model foam system was non-linear for both control (no fire exposure) and fire-exposed tests, as would be expected. However, the concentration of fluorosurfactant within the drainage solution was initially lower, increasing with time. This suggests that the fluorosurfactants are retained within the foam blanket for longer than other constituents of the model foam. This is proposed to result from the unequal probability of rupture in bubbles comprising the foam blanket: as the rate of foam collapse decreases with time, bubbles with lower stability burst until those with a higher persistence and higher surfactant content remain.

Glycine betaine enhanced foam separation for recovering and enriching protein from the crude extract of perilla seed meal

The utilization of agro-food waste into protein products is an alternative solution for global protein shortage and waste management. Perilla (Perilla frutescens L.) seed meal (PSM) is abundant and protein-rich by-products from the oilseed industry. To achieve the industrial production of valuable PSM protein (PSMP), a two-stage foam separation with a low cost and a high efficiency was developed to fractionate the high-concentration PSMP (1.3 times its critical micelle concentration (CMC)) from its crude extract. In the first-stage, glycine betaine (GB), a naturally occurring osmolyte, was used as a green enhancer for the recovery of PSMP. The result of SEM, FTIR, UV–vis and fluorescence spectra demonstrated that GB engaged in cation-π interactions with aromatic residues of PSMP, which made the protein structure unfold and enabled its hydrophobic groups of PSMP to be more exposed. These factors, plus protein aggregation, were responsible for the enhanced interfacial adsorption of PSMP. Its recovery percentage with 0.3 g/L GB (pH 7.0) increased by 52.9% compared to that without GB. Furthermore, an internal component of regular-hexagon hollow prismoid (RHP) was also designed to intensify the foam drainage and raise PSMP enrichment to 7.1 ± 0.3. In the second-stage, PSMP could be further recovered and its total recovery percentage reached 94.5 ± 4.7%. After foam separation, the amino acid composition of PSMP was analyzed by SDS-PAGE and HPLC–UV and its functional properties was also evaluated. These results provide a new insight into enhancing the protein separation from agro-food waste.

Study on foam transport mechanism and influencing factors in foam drainage gas recovery of natural gas well

In order to study the distribution and flow pattern of foam in the wellbore during the process of foam drainage and gas recovery, A coupled model of gas and foam flow in wellbore was established. The distribution characteristics of foam in the wellbore during the process of foam drainage and gas recovery were analyzed through experiments. The concept of foaming efficiency and bubble carrying efficiency were introduced, and the drainage time and liquid accumulation time of foam drainage gas recovery in wellbore were calculated. The research results show that: In the process of foam drainage, there are two states of heterogeneous foam flow and homogeneous foam flow in the wellbore. Under the influence of the high flow rate of natural gas in the wellbore, the migration rate of bubbles near the wellbore is slow. High gas yield and low bubble density are beneficial to the rapid initiation of foam. Due to the double influence of gas carrying force and gravity, bubbles will show relatively complex motion characteristics, and the fluid level height in the wellbore is linearly related to time under different influencing factors in the process of gas well drainage. The research in this article is of great significance for precise drainage of foam drainage gas recovery.

Numerical solutions of the fractal foam drainage equation

The flow of liquid relative to the bubbles is called drainage. This paper presents a study of the numerical solution of a non-linear foam drainage equation with time-fractional derivative. We use the two-scale approach which is formulated by combining the fractional complex transform and the homotopy perturbation method (HPM). With the aid of the fractional complex transform, first, we transform the problem into its differential partner and then HPM is applied to obtain the He’s polynomials which are highly and powerful support for non-linear problems. Further, we put forward the theory of the two-scale approach which reveals the sketch between fractional complex transform and the solution of non-linear foam drainage equation. The significant results illustrate that this approach does not require any assumption while it reduces the heavy calculation without any restrictive variable. This approach also sheds a bright light on practical applications of fractal calculus.