Viscosity Of Water Phase Research Articles

Transient pressure analysis of polymer flooding fractured wells with oil-water two-phase flow

The oil-water two-phase flow pressure-transient analysis model for polymer flooding fractured well is established by considering the comprehensive effects of polymer shear thinning, shear thickening, convection, diffusion, adsorption retention, inaccessible pore volume and effective permeability reduction. The finite volume difference and Newton iteration methods are applied to solve the model, and the effects of fracture conductivity coefficient, injected polymer mass concentration, initial polymer mass concentration and water saturation on the well-test type curves of polymer flooding fractured wells are discussed. The results show that with the increase of fracture conductivity coefficient, the pressure conduction becomes faster and the pressure drop becomes smaller, so the pressure curve of transitional flow goes downward, the duration of bilinear flow becomes shorter, and the linear flow appears earlier and lasts longer. As the injected polymer mass concentration increases, the effective water phase viscosity increases, and the pressure loss increases, so the pressure and pressure derivative curves go upward, and the bilinear flow segment becomes shorter. As the initial polymer mass concentration increases, the effective water phase viscosity increases, so the pressure curve after the wellbore storage segment moves upward as a whole. As the water saturation increases, the relative permeability of water increases, the relative permeability of oil decreases, the total oil-water two-phase mobility becomes larger, and the pressure loss is reduced, so the pressure curve after the wellbore storage segment moves downward as a whole. The reliability and practicability of this new model are verified by the comparison of the results from simplified model and commercial well test software, and the actual well test data.

A fractal relative permeability model for two-phase flow through unsaturated shale porous medium

The accurate calculation of the two-phase relative permeability has a significant impact for effectively characterizing the fluid flow patterns of unsaturated shale reservoir. A new fractal relative permeability model is developed based on two-phase transport feature in confined nanopores, which is upscaled with the aid of fractal theory for two-phase flow through unsaturated shale porous medium. Unlike the earlier models, the presented models considered nanopore wettability, confined viscosity varies with the nanopore diameter (variable water phase viscosity), stress dependence effect, real gas effect, irreducible water saturation and tortuosity effect. The proposed model compares the permeability of single nanopore and multiple nanopores with earlier research, which shows that the fractal relative permeability model agrees well with earlier models and experimental data. The results show that the Monte Carlo model and Abaci experimental model studied by previous researchers are special cases of the proposed fractal model, thus showing that the proposed fractal model has obvious advantages. Further calculations show that 1) The gas phase’s relative permeability gradually decreases with the increase of water saturation; 2) Confined viscosity varies with the nanopore diameter has a greater influence on the inorganic pores and a smaller influence on the organic pores on the relative permeability; 3) The relative permeability of the intersection point in the organic pore is higher than that of the inorganic porous, but the water saturation at the intersection is less than that of inorganic pores. Therefore, it lays a solid foundation for revealing the two-phase flow law of shale porous media.

Nano-scale simulation of oil-water-nanosilica-rock system: Wettability and rheological properties alteration using charged nanoparticles

The real mechanisms beyond the effect of nanoparticles on oil phase displacement by water are still not completely understood. So, in this research, the simultaneous effects of charge and concentration of silica nanoparticles on the oil droplet detachment from calcite surface has been investigated for the first time. For this aim, the parameters of oil droplet contact angle, oil Center Of Mass, Mean Square Displacement and viscosity of water phase have been studied by using molecular dynamics simulation. The thickness of 15°A is selected for all simulations after checking the thickness effect on contact angle results. It was declared that initial shape of oil droplet affected on final contact angle slightly with the relative error of 0.7%. According to the results, silica nanoparticles can lift the oil droplet from the edges because of their interactions with rock surface and water viscosity enhancement which leads to intensify viscous forces and wettability alteration toward more water wet state. In addition, and there is an optimum concentration which decreases with nanoparticle charge rising. In neutral system, the most contact angle alteration occurs in presence of 14 nanoparticles. While the amount of optimum concentration decreased with the growth of nanoparticle's charge and reached to 4 nanoparticles at charge of 0.4 electrons. In addition, there is an optimum charge and it is 0.4e for nanoparticles. The state of rock wettability depends on nanoparticle properties such as charge, size and concentration and this lets us to design a nanoparticle with best performance and least cost.

Formation of egg yolk-modified starch complex and its stabilization effect on high internal phase emulsions

The aim of the present paper was to fabricate egg yolk-modified starch complex at neutral pH as novel emulsifiers to stabilize high internal phase emulsions (HIPEs). Octenyl succinic anhydride (OSA) and hydroxypropyl distarch phosphate (HPDSP) were selected as representative models of surface active and non-surface active polysaccharides. Results of particle diameter, zeta-potential and turbidity indicated that egg yolk-modified starch complex could be formed via electrostatic and hydrophobic interaction. The soluble complex could be formed in egg yolk-OSA starch solutions, which was beneficial to decrease the droplet size and increase the apparent viscosity of HIPEs. However, at the high concentration of HPDSP (3–4 %), the insoluble complex could be formed in egg yolk-HPDSP solutions, which increased the viscosity of water phase and promoted the stability of oil droplets. This work provides a feasible way to successfully fabricate HIPE, which may help to expand their application in the food industry.

Influence of viscosity for oil-in-water and water-in-oil nanoemulsions production by SPG premix membrane emulsification

Oil-in-water and water-in-oil nanoemulsions are interesting carriers for respectively oil soluble and water soluble actives. In this study, oil-in-water (O/W) and water-in-oil (W/O) nanoemulsions were prepared by premix membrane emulsification. A coarse emulsion (premix) was injected thanks to a high pressure pump through a Shirasu Porous Glass (SPG) membrane with pore size of 0.5μm in order to reduce and homogenize the droplet size. The effect of viscosities on the pressure and droplet size was investigated: the water phase viscosity by increasing glycerol concentration, the oil phase viscosity with mineral oils of different viscosities and the overall emulsion viscosity by increasing the dispersed phase content of the emulsion. The pressure required to break up the droplets inside the membrane pores ΔPdis did not depend on viscosities, while the pressures generated by the flows through the pipe ΔPpipe and the membrane ΔPflow were proportional to the viscosity of the overall emulsion. W/O nanoemulsions were more difficult to produce and to characterize but thanks to the original set-up working at pressures up to 65 bar and high flowrates, W/O mineral oil nanoemulsions were produced with mean droplets size around 600nm and flow rate of 50mL/min.

Influence of Pectin on the Stability of Whey Protein Isolate Stabilized Emulsion for Encapsulating Lutein

The effect of pH, thermal treatment and storage stability of lutein-loaded emulsion prepared with whey protein isolate and stabilized by low and high methyl pectin was investigated. Results showed that emulsions prepared in the absence of pectin were highly unstable and flocculated with increasing temperature (60-120C) and this was attributed to protein denaturation. On the other hand, the additional of second layer of high methyl or low methyl pectin improved the stability of the emulsion against the environmental stresses. This was due to formation of steric barrier onto droplets. Furthermore, high methyl pectin showed a better stability than low methyl which was attributed to increased viscosity of water phase. The double layer emulsions of whey protein isolate and high methyl pectin exhibited a better physical and chemical stability than single layer emulsions. Additionally, high methyl pectin double layer increased lutein retention during the 5 weeks storage at different temperatures. Therefore, these findings could be useful for preparation of stable lutein emulsion.

裂缝性碳酸盐岩油藏凝胶堵水方案优化模拟研究

In order to avoid S Oilfield water ratio rising rapidly and slow down production decline, we need to implement plugging process with polymer gel. Through researches on the mechanism of the polymer gel, and factor in elements during underground water plugging process including underground gel chemical reaction, loss of various chemical agent, adsorption and retention of chemical component, degradation of gel, and the influence to water phase viscosity from flow properties and the chemical components, etc., we can establish a movable gel three-phase seven components numerical model. By simulative calculation, we are able to get a reasonable way of gel injection and injection volume, providing an effective way to improve the effect of oil field exploitation, slow down production decline and improve recovery efficiency.

Synthesis and properties of silanized waterborne polyurethane/graphene nanocomposites

A series of silanized waterborne polyurethane (WPU)/graphene oxide (GO) chemical hybrids were synthesized from polycaprolactone diol, isophorone diisocyanate, dimethylol butanoic acid, and (3-aminopropyl) triethoxysilane with GO as multifunctional crosslink as well as reinforcing filler. With the addition of GO, dispersion size greatly decreased due to the increased water phase viscosity, while it increased after chain extension reaction due to the migration of GO into the PU particles. The GO covalently bonded to WPU via the sol–gel type reaction augmented contact angle, glass transition temperature (Tg), hardness, and Young’s modulus of the cast film up to 1 %. However, the effects were less pronounced at high content (1.5 %) due to the agglomeration of GO particles.

Preparation of uniform monomer droplets using packed column and continuous polymerization in tube reactor

A two-step continuous emulsification and polymerization process was developed in which monomer droplets having narrow size distribution were prepared and polymerized while retaining their monodispersity. In the emulsification step, a column packed with glass beads, of diameters ranging from 70 μm to 1 mm, was used to prepare a monomer O/W emulsion. Monomer droplets were dispersed with an aqueous solution of poly(vinyl alcohol) (PVA). The droplet size and -distribution was studied with respect to the effects of diameter of glass beads, concentration of PVA in water phase, degree of polymerization of PVA, ratio of mass flow of water phase to that of oil phase, linear velocity of water phase and viscosity of water phase and oil phase. Droplet size was found to be strongly dependent on the diameter of the packed glass beads, while the droplet size distribution was affected by the viscosities of the continuous and dispersed phases. Increasing the viscosity of the dispersed phase by addition of poly(styrene) to the monomer mixture resulted in a narrow size distribution of glycidyl methacrylate–ethylene glycol dimethacrylate droplets. Furthermore, these initiator-containing monomer droplets were polymerized by heating in a tubular reactor, from which polymer particles with a narrow size distribution could be synthesized.

Which One Is More Important in Chemical Flooding for Enhanced Court Heavy Oil Recovery, Lowering Interfacial Tension or Reducing Water Mobility?

A total of 33 sandpack flood tests were carried out to investigate the effects of interfacial tension (IFT) and water-phase viscosity on enhanced heavy oil recovery by chemical flooding. The amount of oil recovered by alkaline-only flooding increased sharply with the NaOH concentration in the range of 0.3−0.5 wt %. The oil recovery only varied slightly with the changing alkaline concentration outside the range. The coexistence of the surfactant and NaOH reduced the IFT between the oil and aqueous phase to an ultra-low level. However, the amount of oil recovered by alkaline/surfactant flooding only increased slightly with an increasing NaOH concentration up to a threshold value of 0.5 wt %. Beyond this threshold value, the recovery efficiency stopped increasing with the alkaline concentration and its value was lower than that of the alkaline-only displacing process. The addition of a polymer improved the tertiary oil recovery by increasing the viscosity of the water phase, although it also increased the IF...

Numerical Simulation of Oil Recovery After Cross-Linked Polymer Flooding

Abstract Cross-linked polymer flooding can increase oil recovery 10 to 20% over conventional waterflooding, while using a lower concentration of polymer than conventional polymer flooding. Based on production data from a developed oil field, the average incremental oil recovery by polymer flooding is only 10%, indicating that much of the oil is bypassed. We need to know how this bypassed oil is distributed to design an optimal development strategy. Numerical simulations have been performed to study the mechanisms of polymer flooding. For the coarsening downward sedimentary cycle, the simulation model was divided into five layers with average geometric permeabilities of 100 mD, 300 mD, 500 mD, 980 mD and 2,190 mD, respectively. Five spot well patterns with 180 m distance between each injector and producer has been used. The injecting well was controlled by an injection rate of 100 m3/d and shut down as the water ratio reached 98%. Cross-linked polymer injection was introduced after the water cut was as high as 90% and stopped as the water cut reached 98%. It was found that most of the residual oil after polymer flooding existed in small areas far away from the diagonal line for heterogeneous reservoirs, and in layers with low or intermediate permeabilities for cycle reservoirs. Introduction The Xiaermen Oil Field lies in Biyang County, Henan Province. It is located in the middle of a large northeast fault edge, to the east of Biyang Sag, Nanxiang Basin (Figure 1). The structure of this field is a brachy-anticline in an east-west direction complicated by four major faults and many minor faults adjacent to the main oil-bearing area. Among these faults, a series of small faults to the east were originated from the big fault (Figure 1). The maximum height of the trap is 275 m. The Xiaermen sand was deposited by deltaic fans(1). Considerable variation in sand thickness occurring over short lateral distances is characteristic of this particular deposit and thick layers with high permeability are patchy and isolated. The sediment underlying the project area is finely grained and relatively clean quartz sand. The average porosity is about 24% and the mean geometric permeability is 2 µm2. The porosity and permeability is generally high, but fairly heterogeneous. The petroleum industry has recognized the problem of inefficient oil recovery by conventional waterflooding. Therefore, extensive research has been conducted using new techniques of enhanced oil recovery (EOR) of the reservoirs(2). Polymer flooding is a significant method used for this purpose, in which the mobility of the displacing phase can be reduced effectively by the addition of small amounts of water-soluble polymers. Polymer flooding will enhance oil recovery by increasing the water phase viscosity, improving the water/oil mobility ratio and improving sweep efficiency. Polymer flooding may have beneficial effects in relatively homogeneous oil reservoirs. However, the improvements might be more modest in a heterogeneous reservoir. By adding a cross-linking agent into the polymer and then forming a 3D reticulate texture through the intermolecular cross-linking, a cross-linked polymer can increase the viscosity of the injected fluid.

Microfluidic Approach for Rapid Interfacial Tension Measurement

A novel microfluidic approach to measure interfacial tension of immiscible fluids rapidly is reported. This method rests upon quantitative force balance analysis of drop formation dynamics in a coaxial microfluidic device. The values of interfacial tension for several two liquids without/with surfactants are measured. These measurements compare well with those measured by the commercial interfacial tensiometry. The viscosity of water phase fluid can also be accurately measured in the same microfluidic device. Several model systems with interfacial tension from 1.0 to 10.0 mN/m and water phase viscosity from 1.0 to 10.0 mPa.s are tested in this work.

Effect of added oil and modified starch on rheological properties, droplet size distribution, opacity and stability of beverage cloud emulsions

Optical and rheological properties of beverage cloud emulsions as a function of water-phase and oil-phase concentrations were investigated. The specific gravity of phases, particle size distribution and creaming stability of prepared emulsions in diluted forms were evaluated. Combinations of emulsions with added starch (3.74–18.7% w/w, with oil at 3.74% w/w) and oil (7.48–18.7% w/w with starch at 11.2% w/w) were used. The specific gravity of oil phase was adjusted using a constant combination of weighing agents [sucrose acetate isobutyrate and brominated vegetable oil] and different level of coconut oil. Oil-phase concentration had a significant effect (P<0.05) on increasing the opacity of emulsion. Increase in modified starch concentration for all water phases decreased the flow behavior index while oil phase at any given concentration of coconut oil contributed to a Newtonian behavior. Raise in viscosity of emulsions was more pronounced as oil concentration increased and shear thinning behavior of oil added emulsions was associated with droplet flocculation. Creaming in acidified sugar solution of 11°Bx and pH 3 was observed when the oil-phase specific gravity decreased and sedimentation occurred at the lower viscosity of water phase. Examination of dynamic rheological properties of emulsions revealed that all oil added emulsions showed viscous behavior with the delta degree (G″/G′) greater than 74 at maximum frequency level (50rad/s) and decreased along with increasing the oil level. The solid or elastic behavior was related to those emulsions that exhibited sedimentation with the delta degree lower than 35.