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Feng R.,Southwest Petroleum University | Zhou Y.,Southwest Petroleum University | Guo Y.,Southwest Petroleum University | Guo Y.,Sichuan Guangya Polymer Chemical Company | And 3 more authors.
Oilfield Chemistry | Year: 2016

In order to understand the effect of the elasticity of polymer flooding system on the displacement efficiency of heavy oil with high viscosity, a flat sand inclusion visual flooding experimental device, which was used to simulate reservoir homogeneity, was established. Grey value method, a new quantitative evaluation method of oil displacement efficiency, was proposed. The elasticity of two typical polyacrylamide polymer, partially hydrolyzed polyacrylamide (HPAM) and hydrophobically associating polyacrylamide (HAWSP-2), and its impact on the displacement efficiency of heavy oil were studied. The experimental results showed that the shear resistance effect of HAWSP-2 was better than that of HPAM at low shearing rate, which was due to the existence of hydrophobic association. The flow index, the first normal stress difference, yield stress and deformation recovery rate of HPAM and HAWSP-2 with 100 mPa · s was 0.384, 20.60 Pa, 0.29 Pa, 35.67% and 0.204, 67.50 Pa, 1.25 Pa, 183.15%, respectively, indicating the elasticity of HAWSP-2 was greater than that of HPAM. In flooding experiment, with increasing viscosity of heavy oil, the oil displacement efficiency of HPAM and HAWSP-2 both decreased. But the oil displacement efficiency of HAWSP-2 was higher than that of HPAM. When heavy oil with same viscosity was flooded, four elastic parameters were arranged according to their changes corresponding the increase of per oil displacement efficiency in following order: deformation recovery rate>yield stress>the first normal stress difference>flow index, that was to say, the contribution of deformation-resilience, yield stress, the first normal stress difference and flow index to oil displacement efficiency increased. The effect of polymer elasticity on heavy oil displacement efficiency was positive correlation, and the flow index was the dominant factor of the effect of polymer elasticity on oil displacement efficiency.

Feng K.-S.,State Key Laboratory of Oil and Gas Reservoirs Geology and Exploration | Feng K.-S.,Southwest Petroleum University | Guo Y.-J.,State Key Laboratory of Oil and Gas Reservoirs Geology and Exploration | Guo Y.-J.,Sichuan Guangya Polymer Chemical Company | And 6 more authors.
Acta Polymerica Sinica | Year: 2016

The hydrophobic association and polyelectrolyte effect of hydrophobically associated water-soluble polymers (HAWSP) were eliminated in solvents containing 50% (volume percent concentration) 1, 3-propylene glycol, 0. 2 mol/L NaCl and water that could make molecules of HAWSP disperse in dilute solutions. Then the polymers of different molecular weights were split through the microporous membrane equipment with different aperture microporous membranes according to the principle of membrane aperture separation. The cumulative percentage of each fraction was calculated through the quantity of each fraction polymer solution which was measured by the curve of percolate quantity-filtration time fitted with a quadratic equation, and the concentration of each fraction polymer solution was measured by spectrophotometry. The Mark-Houwink equation [η] = 0. 182M0.586 of HAWSP which was used to accurately determine the molecular weight of each HAWSP fraction, was calibrated through the static light scattering and capillary tube viscosity methods. The molecular weight distribution curve was determined according to the molecular weight (M) and cumulative percentage (W) of each fraction by using the 4-parameter equation curve. The method of microporous membrane grading to determine the molecular weight distribution of HAWSP was compared with the method of dynamic light scattering for measurement of particle size, the results of the two methods were consistent with each other.

Chen Q.-S.,University of Queensland | Kang Q.-J.,Southwest Petroleum University | Kang Q.-J.,Sichuan Guangya Polymer Chemical Co. | Li H.-B.,Southwest Petroleum University | Li H.-B.,Sichuan Guangya Polymer Chemical Co.
Xinan Shiyou Daxue Xuebao/Journal of Southwest Petroleum University | Year: 2011

The new initiating system for synthesis of acrylamide-based polymers has attracted much attention and been the focus of increasing polymer molecular weight in recent years. The performance of polymerization, characteristic and range of application of aqueous azo initiator has been investigated and the aqueous azo initiators can be used for the preparation of high molecular weight acrylamide-based polymers and its derivatives, which demonstrates abroad application prospect. The effect of difunctional initiator and amino functional monomer on molecular weight are also discussed. The initiating system of the new kind of cryogenic compound initiators containing potassium persulfate, ammonia water, urea, azo-(2-amidinopropane) dihydrochloride, functional monomer MP are believed to be able to be used for the preparation of ultrahigh molecular weight acrylamide-based polymers.

Geng X.F.,Southwest Petroleum University | Hu X.Q.,Southwest Petroleum University | Jia X.C.,BGP Inc. | Luo L.J.,Sichuan Guangya Polymer Chemical Company Ltd
Colloid and Polymer Science | Year: 2014

Solutions of a novel zwitterionic gemini surfactant, 1,2-bis[N-ethyl-N- (sodium 2-hydroxyl-3-sulfopropyl)-dodecyl-ammonium] ethane betaine (DBA 2-12), in presence of sodium salicylate (NaSal) can form wormlike micelles and thereby show a viscoelasticity. At low molar ratio of NaSal/DBA2-12, R∈≤0.3, the systems behaved like a Newton fluid. However, as the R increased, the systems exhibited shear-thinning behavior. The zero-shear viscosity η ;bsubesub increased dramatically with increasing R and peaked with R∈=∈0.8 at a value of 18.8 Pa s. This was attributed to the formation of long wormlike micelles (1.6∈~≤∈2.9 μm) and network structure confirmed by scanning electron microscopy. Further increase in R beyond 0.8 resulted in a slight decrease in η ;bsubesub, which may be caused by the branched micelles formed at high salt concentration. In addition, the tested systems showed a Maxwellian behavior at lower frequencies, but deviated from the Maxwellian mode at higher frequencies. © 2013 Springer-Verlag Berlin Heidelberg.

Bao J.,Southwest Petroleum University | Luo P.,Southwest Petroleum University | Guo Y.,Southwest Petroleum University | Xiong Y.,Sichuan Guangya Polymer Chemical Company
Oilfield Chemistry | Year: 2015

Viscosity change regularity of adding novel non-ionic surfactants (GS-1, GS-2 and GS-3) with different hydrophobic chain length to non-crosslinked associative structural fracturing fluid using hydrophobic associative polymer as thickener was investigated. The number of carbon atoms in hydrophobic tail of GS-1, GS-2 and GS-3 was 6, 10 and 14, respectively. GS-3 was selected as the optimal tackifying adjuvant for the fracturing fluid accordingly. The optimum concentration and application temperature range of GS-3 were obtained. And the influence of GS-3 on the viscosity and viscoelasticity of base fracturing fluid was also investigated. The results of experiments showed that the apparent viscosity of fracturing fluid could be greatly increased by adding traces GS-3 (0.03%-0.05%). The optimum concentration of GS-3 was the concentration corresponding to the peak apparent viscosity of complex system and its applicable temperature range was 30-90°C. Within the test concentration range, the apparent viscosity of system increased first and then decreased, the change trend accorded with Biggs's 3 periods model. When the temperature increased from 30°C to 120°C, the apparent viscosity of system also increased first and then decreased. The maximum tackifying rate was 168% at 63°C. The viscoelasticity of fracturing fluid was also enhanced simultaneously. The storage modulus could be increased 1-10 times according to the concentration of thickener. So the dosage of thickener could be greatly decreased by using GS-3 as tackifying adjuvant. © 2015, China International Book Trading Corp. (Guoji Shudian). All rights reserved.

Guo Y.,Southwest Petroleum University | Zheng C.,Sichuan Guangya Polymer Chemical Company | Yang H.,Sichuan Guangya Polymer Chemical Company | Liang Y.,Sichuan Guangya Polymer Chemical Company
RSC Advances | Year: 2016

In this work association behaviors of a carbazole-labeled hydrophobically modified polyacrylamide were studied by fluorescence spectroscopy in order to reveal the aggregation-induced spectral features. Both emission and excitation spectra reveal three distinct regimes for the association process of carbazole-labeled polyacrylamide with increasing concentration. In regime I, there is only a linear relationship between fluorescence intensity and concentration which was ascribed to unimer regime without aggregation. While a marked change in spectral shape could be observed in regimes II and III beyond the critical aggregation concentration. In regime II there is an aggregation-induced red shift in the excitation spectra and a decrease in 0-0 transition in emission spectra. In regime III aggregation-induced quenching was observed. These spectroscopic features of the excitation and emission spectra imply the formation of disordered J-aggregates by carbazole units during the association process, which could be employed to analyse the structural transition of hydrophobically modified polyacrylamide solutions. © The Royal Society of Chemistry 2016.

Guo Y.,Southwest Petroleum University | Guo Y.,Sichuan Guangya Polymer Chemical Company | Liang Y.,Southwest Petroleum University | Yang X.,Sichuan Guangya Polymer Chemical Company | And 4 more authors.
Journal of Applied Polymer Science | Year: 2014

Poly(acrylamide/sodium acrylate/N-dodecyl acrylamide)s [poly(AM/NaAA/C 12AM)s] with different hydrophobic microblock lengths (N H's) were prepared by the micellar copolymerization of acrylamide and sodium acrylate with a low amount of N-dodecyl acrylamide (0.2 mol %), and the molecular structure was characterized by Fourier transform infrared spectroscopy, 1H-NMR, and static light scattering. A combination of experiments involving viscosity measurement, fluorescence, and conductometry was applied to investigate the effect of NH on the interaction strength and binding capacity between poly(AM/NaAA/C12AM)s and C 12H25SO4Na [sodium dodecyl sulfate (SDS)]. The viscosity, I3/I1 (the intensity ratio of the third vibrational band to the first band of pyrene molecules), and conductivity of the mixed system of copolymers with SDS all had different variation trends with the concentration of SDS. The binding capacity of the copolymers with SDS was calculated according to quantitative differences between the critical micelle concentration of the pure SDS solution and the mixed system. All of the results show that the interaction strength of SDS with the copolymers rose, and the binding capacity decreased with increasing NH. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40633. Copyright © 2014 Wiley Periodicals, Inc.

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