FUEL
·
2021
·
IF 6.609
Xinjie Luo,Pengfei Zheng,Ke Gao,Bing Wei,Yujun Feng
Water-alternating-CO 2 gas (WAG) flooding is a common technique to enhance oil recovery via improving CO 2 sweep efficiency, but serious gas channeling may still occur, especially in reservoirs with strong heterogeneity, due to a poor blocking capacity of aqueous slugs to the “channeling” pathway induced by their low viscosity. Herein, a copolymer whose aqueous solution viscosity can be increased by both heat and CO 2 was developed and added into the aqueous slug to control gas channeling and increase oil recovery during enhanced WAG processes. The copolymer was synthesized by grafting poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) onto the triblock copolymer, Pluronic F127, PEO 100 -PPO 65 -PEO 100 . The aqueous copolymer solutions can be thickened/gelled by heating due to the formation of micelles as the physical cross-link and their entanglements even at a concentration as low as 0.2 wt%, and viscosified by bubbling CO 2 thanks to expanded copolymer coils caused by electrostatic repulsion-induced chain extension of protonated PDMAEMA chains. Notably, thermo- and CO 2 -triggered viscosifying can work synergistically and they are completely reversible upon cyclically heating/cooling the copolymer solutions and bubbling/removing CO 2 into/from the aqueous phase, respectively. In WAG flooding tests using two parallel cores, gas channeling was mitigated by blocking high-permeability cores due to in-situ thermo-induced gelation and CO 2 -triggered thickening of copolymer slugs, thus diverting chase fluids into unswept low-permeability cores and enhancing 21–22% total oil recovery than the conventional and HAPM-enhanced WAG modes. Importantly, owing to the characteristics of low initial viscosity, single component, and thermo-gelation, this dually-responsive copolymer possesses high injectivity and satisfactory gelation control. This work could enlighten the design of novel dual/multiple stimuli-thickening polymers used for channeling control and enhanced oil recovery.
研究领域:
石油工程
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材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Micro & Nano Letters
·
2017
·Vol. 12
·期 9
·633-637
·
IF 0.723
Jianwu Sun,Lingxiao Li,Jie Shen,Xiaoteng Zhou,Junpei Li,Chengyou Kan
A new kind of poly(methyl methacrylate–butadiene–styrene) (MBS) core/shell latex nanoparticles with amine groups in the shell was prepared via multistep seeded emulsion copolymerisation of styrene, methyl methacrylate and N,N-diethylaminoethyl methacrylate (DEAEMA) onto the poly(styrene–butadiene) seed latex in the presence of anionic emulsifier, and their CO 2 -triggered coagulating properties were investigated. Results showed that the emulsion polymerisation could be performed smoothly, and the coagulating time of the amine-containing MBS latexes depended on the DEAEMA content and solid content. The MBS solid powder could be easily obtained by drying and grinding without any extra treatment after the coagulation. A coagulating mechanism of the in-situ opposite charge interaction and the transformation from sodium laurate to lauric acid was proposed, which was demonstrated by transmission electron microscopy, dynamic light scattering, surface tension and Zeta potential measurements. This facile and smart method might open up industrial potential in cost-effective and environment-friendly latex coagulation.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Coatings Technology and Research
·
2021
·Vol. 18
·期 4
·989-998
·
IF 2.382
Xu Liangfeng,Wang Zhaofei,Yang Gongwen,Zhang Guobing,Wei Haibing,Fang Huagao,Ding Yunsheng
Traditional waterborne polyurethane (WPU) has poor water resistance because of the incorporation of permanent hydrophilic groups, such as carboxyl group or ammonium salt, into polymer chains. Therefore, developing WPU with excellent water resistance and mechanical properties is highly desirable for industrial applications. In this study, CO 2 -triggered hydrophobic/hydrophilic switchable waterborne polyurethane–acrylate (WPUA) containing methyl methacrylate (MMA) units were designed and synthesized. The molecular structure, hydrophobic/hydrophilic switchable behavior, water resistance, and mechanical properties were systematically investigated and characterized. The WPUA with 10 wt% MMA exhibited a low water uptake (2.15 wt%) and linear swelling ratio (0.17 L%), as well as a high tensile strength (16.7 MPa) and modulus (85.9 MPa), which were much higher than those of the pristine WPU. This study indicated that the CO 2 -triggered WPUA dispersed stably as latex particles in water and possessed excellent water resistance and mechanical properties after the film formation.
研究领域:
材料科学
·
聚合物化学
·
表面科学
✓ 已验证
产品关联
DOI
高影响因子
LANGMUIR
·
2019
·
IF 3.683
Zidong Zhang,Yuming Tu,Hui Yu,Weidong Liu,Zhiyong Zhou,Zhongqi Ren
Extraction is a common approach to separating aromatics and alkanes, but solvent recovery remains an issue. The polarity, hydrophobic/hydrophilic balance, and other properties of switchable solvents can be reversibly changed in the presence of various triggers, and taking advantage of this property can greatly simplify the process of solvent recovery. In this work, quaternation and anion exchange were used to prepare several switchable solvents by introducing OH– ions to derivatives of the amidine compound 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). The resulting compounds exhibited reversible switching in response to exposure to CO2. Using toluene/n-heptane as a model hydrocarbon mixture, a reversible phase change extraction process was established. Among the four switchable solvents prepared, [C2DBU]OH showed the highest selectivity value and so was used to investigate the effect of various parameters on hydrocarbon separation. The extraction process was found to rapidly reach equilibrium when a two-phase system was generated by bubbling CO2 through the extraction mixture. Increasing the proportion of the solvent increased the selectivity for toluene, while a 1:1 ratio between the solvent and the toluene/n-heptane mixture enhanced the extraction. Increasing the initial toluene concentration reduced the selectivity for toluene, with a value of 5.97 at a toluene concentration of 20%. The switchable solvent recovered its initial state when heated at 60 °C for 1 h. Upon being reused after removal of CO2, the solvent exhibited poor separation characteristics, although the selectivity coefficient remained constant at approximately 3.1 during 10 regenerations. Finally, the mechanism of the switchable solvent effect and modeling of experimental data were investigated.
研究领域:
化学工程
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分离科学
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溶剂化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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