Showing papers by "Mingwei Zhao published in 2019"

Precisely Tailoring Bubble Morphology in Microchannel by Nanoparticles Self-assembly

Abstract: Precisely tailoring bubble morphology is always a long-standing great challenge. In this work, a facile and scalable method to generate nonspherical bubbles with long-term stability is proposed. Taking advantage of the electrostatic interaction between silica nanoparticles (SNPs) and cationic surfactants, the SNPs are decorated with surfactants and endowed with interfacial activity. Due to the rearrangement of surfactants, the decorated SNPs transform to a kind of Janus particles at the gas–liquid interface. By precisely manipulating the surface activity, packing density, and jamming of Janus SNPs at the bubble surface, four different shapes such as oblaten-like, bullet-like, tadpole-like, and worm-like bubble were obtained continuously in the microchannel. Herein, our method to generate bubbles with a prescribed shape poses opportunities for gas microreactor, cavity material, gas storage, and provide a platform to study the applicable scope of the Young–Laplace equation.

A novel strategy to create bifunctional silica-protected quantum dot nanoprobe for fluorescence imaging

Abstract: Quantum dots (QDs) as fluorescence probes have attracted increasing attention for their fluorescence imaging applications. In this work, we developed a novel strategy to create bifunctional silica-protected QD (BSQD) nanoparticles as nanoprobes for fluorescence imaging. The thiol-ene click reaction of monounsaturated fatty acid salts with mercapto silane as an efficient method for the synthesis of the bifurcated surface modifier was presented. BSQD nanoprobes were prepared by a facile one-pot method. The whole reaction process was carried out in an aqueous solution under relatively low temperature, which makes the synthesis environment eco-friendly and the products cost-effective. The synthesized BSQD nanoprobes have a structure consisting of hydrophilic and hydrophobic arms that afforded an amphiphilic feature to the silica-protected QD (SQD) nanoparticles. The separated solid BSQD nanoprobes could be well dispersed into aqueous solution once again, and the quantum yield of the BSQD nanoprobes was higher than that of the SQD naoprobes. BSQD nanoprobes exhibited high interfacial activity, strong photostability and good biocompatibility. BSQD nanoprobes were successfully applied for fluorescence imaging. The strategy for the construction of the functionalized SQD nanoparticles provides a promising approach for modifying the surface of materials containing QDs.

Zirconium gel particle combination flooding system and preparation method thereof

Abstract: The invention belongs to the field of oilfield chemistry and specifically relates to a zirconium gel particle combination flooding system. The zirconium gel particle combination flooding system comprises multi-scale 1 zirconium gel particles, polyether nonionic surfactant, and water as mixing liquid; the weight percentage of multi-scale zirconium gel particles in the combination flooding system ranges from 0.16% to 0.24%; the weight percentage of polyether nonionic surfactant in the combination flooding system ranges from 0.1% to 0.4%; the rest is water, and the sum of the weight percentage of the each component is 100%. The multi-scale zirconium gel particles and polyether nonionic surfactant of the present invention perform good synergistic effect, which reduces the oil/water interfacial tension to the order of magnitude of 10−3 mN/m, significantly improves the displacing efficiency of the flooding agent, avoids the adverse effects caused by polymer viscosity loss in binary combination flooding or ternary combination flooding and the adverse effects caused by alkalis, as well as improves the flooding performance of the combination flooding system.

Flow behaviors of a viscoelastic polymer solution at 3D micro pore-throat structure

Abstract: Polymers are abundantly used in oil production industry, especially in enhanced oil recovery process. The underground oil reservoir is a kind of porous media where complex microscopic geome...

Experimental Study of Organic Alkali Enhancing Polymer/Surfactant Flooding Oil Recovery

Abstract: Oil recovery has a great relationship with the interfacial tension (IFT) between displacing fluids and crude oil in chemical flooding. Alkalis such as sodium hydroxide and sodium carbonate are often used to enhance the applied performances of surfactant and polymer. In this paper, two kinds of organic alkalis, triethylamine (TEA) and monoethanolamine (MEA) are applied together with given surfactant (OC-1) and polymer (APP-4) to form a novel organic alkali/surfactant/polymer (OASP) system. The optimum applied concentrations of three components are selected by referring to the dynamic IFT between their aqueous solutions and oil. The formula of this novel ultralow IFT OASP system is obtained considering the better performance and relatively lower concentration of MEA. The OASP system can reduce IFT to the value lower than 10−3 mN/m when prepared with the brine. Core displacing experiments are also conducted and the results confirmed that the OASP system can displace the oil recover efficiently. Finally, microscopic model was successfully used to investigate the relevant mechanisms of OASP system on enhanced oil recovery. Microscopic flooding experiment confirmed that the transformation and mobilization of the residual oil caused by the ultralow IFT is important for the OASP compound system for enhancing oil recovery.

Screening and Evaluation on Compound Profile Control System for Reutilization of Residual Polymer in Formation

Abstract: Flocculants for the reutilization of residual polymer in formation can be divided into two categories; the inorganic flocculants and the organic flocculants, each has its own advantages and disadvantages, and compounding inorganic and organic flocculants is promising method to make up shortcomings comes from onefold flocculant. The compound system was preliminarily screened based on the compatibility of organic and inorganic flocculants in the same system and then the optimum formula was selected based on the comparison of properties of compound systems with varying volume ratio and concentration ratio between inorganic and organic flocculants; these properties include injectivity, plugging performance, erosion resistance property and enhanced oil recovery. The screening tests were conducted under the condition simulating the existence and distribution of residual polymer in formation. The optimum formula of compound system for the reutilization of residual polymer in offshore reservoir is consist of 0.5 wt% stabilized Na-bentonite (YG340-1) and 1.0 wt% modified cationic starch; the former is inorganic flocculant with the latter the organic one. The optimized volume ratio between inorganic and organic flocculants in the selected compound system is 5:2. In compound system, the inorganic flocculant and organic flocculant enjoy complementary advantages to motivate better performance than single flocculant system in injectivity, plugging performance, erosion resistance property, with an exciting enhanced oil recovery in laboratory study.

Preparation and Evaluation of Acid Gel Fracturing Fluid with Temperature Resistance

Abstract: Carbonate reservoir takes large proportion of oil reservoirs in the world. Acid fracturing, as an effective stimulation method, has been widely used in carbonate and sandstone reservoir, and the results of acid fracturing largely depend on the quality of fracturing fluid. Acid gel fracturing fluids combine the advantage of matrix acidizing and hydrofracture. Acid gel carries proppants and forms fracture, which has longer distance and higher conductivity. A sort of acid gel fracturing fluid with good temperature resistance (130 °C) is developed. The gelling time could be adjusted by the composition and dosage of crosslinking liquid. The rheometer was used to study the temperature resistance, shearing tolerance. The retarding ability, suspended sand property, and gel breaking property had also been investigated. The viscosity of the acid gel is over 150 mPa s in 130 °C. The viscosity is reduced and less than 15 mPa s after gel breaking. This acid gel had the advantaged of crosslinking time controllable, strong suspended sand property, and perfect temperature resistance. This system is suitable for 130 °C carbonate reservoir acid fracturing.