Emulsifier-free poly（methyl methacrylate-styrene） [P（MMA-St）] nanospheres with an average particle size of 100 nm were synthesized in an isopropyl alcoholwater medium by a solvothermal method. Then, through radica...Emulsifier-free poly（methyl methacrylate-styrene） [P（MMA-St）] nanospheres with an average particle size of 100 nm were synthesized in an isopropyl alcoholwater medium by a solvothermal method. Then, through radical graft copolymerization of thermo-sensitive mono- mer N-isopropylacrylamide （NIPAm） and hydrophilic monomer acrylic acid （AA） onto the surface of P（MMA- St） nanospheres at 80 ℃, a series of thermo-sensitive polymer nanospheres, named SD-SEAL with different lower critical solution temperatures （LCST）, were prepared by adjusting the mole ratio of NIPAm to AA. The products were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, particle size distribution, and specific surface area analysis. The temperature-sensitive behavior was studied by light transmittance tests, while the sealing performance was investigated by pressure transmission tests with Lungmachi Formation shales. The experimental results showed that the synthesized nanoparticles are sensitive to temperature and had apparent LCST values which increased with an increase in hydrophilic monomer AA. When the temperature was higher than its LCST value, SD- SEAL played a dual role of physical plugging and chemical inhibition, slowed down pressure transmission, and reduced shale permeability remarkably. The plugged layer of shale was changed to being hydrophobic, which greatly improved the shale stability展开更多
Aimed at the disadvantages of secondary damage to oil layers caused by the conventional bull-heading water control technique, a thermo-sensitive temporary plugging agent for water control was synthesized by water solu...Aimed at the disadvantages of secondary damage to oil layers caused by the conventional bull-heading water control technique, a thermo-sensitive temporary plugging agent for water control was synthesized by water solution polymerization and applied in the field with a new secondary temporary plugging technique. The optimization and performance evaluation of thermo-sensitive temporary plugging agent were carried out through laboratory experiments. The optimized formula is as follows:(6%-8%) acrylamide +(0.08%-0.12%) ammonium persulfate +(1.5%-2.0%) sepiolite +(0.5%-0.8%) polyethylene glycol diacrylate. The thermo-sensitive temporary plugging agent is suitable for formation temperatures of 70-90 ?C, it has high temporary plugging strength(5-40 k Pa), controllable degradation time(1-15 d), the apparent viscosity after degradation of less than 100 m Pa?S and the permeability recovery value of simulated cores of more than 95%. Based on the research results, secondary temporary plugging technique was used in a horizontal well in the Jidong Oilfield. After treatment, the well saw a drop of water cut to 27%, and now it has a water cut of 67%, its daily increased oil production was 4.8 t, and the cumulative oil increment was 750 t, demonstrating that the technique worked well in controlling water production and increasing oil production.展开更多
Photoanodic properties greatly determine the overall performance of quantum-dot-sensitized solar cells（QDSCs）. In the present report, the microdynamic behaviors of carriers in the nanocomposite thin-film, a Zn Se QD...Photoanodic properties greatly determine the overall performance of quantum-dot-sensitized solar cells（QDSCs）. In the present report, the microdynamic behaviors of carriers in the nanocomposite thin-film, a Zn Se QD-sensitized mesoporous La-doped nano-TiO2 thin-film, as a potential candidate for photoanode, are probed via nanosecond transient photovoltaic（TPV） spectroscopy. The results confirm that the L-Cys ligand has a dual function serving as a stabilizer and molecular linker. Large quantities of interface states are located at the energy level with a photoelectric threshold of1.58 eV and a quantum well（QW） depth of 0.67 eV. This QW depth is approximately 0.14 eV deeper than the depth of QW buried in the Zn Se QDs, and a deeper QW results in a higher quantum confinement energy. A strong quantum confinement effect of the interface state may be responsible for the excellent TPV characteristics of the photoanode. For example, the peak intensity of the TPV response of the QD-sensitized thin-film lasts a long time, from 9.40 × 10^（-7） s to 2.96 × 10^（-4） s,and the end time of the PTV response of the QD-sensitized thin-film is extended by approximately an order of magnitude compared with those of the TiO2 substrate and the QDs. The TPV characteristics of the QD-sensitized thin-film change from p-type to n-type for the QDs before and after sensitizing. These properties strongly depend on the extended diffusion length of the photogenerated carries and the reduced recombination rate of photogenerated electron-hole pairs, resulting in prolonged carrier lifetime and an increased level of electron injection into the TiO2 thin-film substrate.展开更多
基金financial support from the National Science Foundation of China (Nos. 51374233, 51474235)the Postdoctoral Innovative Project Foundation of Shandong Province (No. 201602027)+2 种基金the Qingdao Postdoctoral Applied Research Project (No. 2015242)the Fundamental Research Funds for the Central Universities (No. 15CX06021A)the Graduate Student Innovation Project from China University of Petroleum (East China) (No. YCX2015011)
文摘Emulsifier-free poly（methyl methacrylate-styrene） [P（MMA-St）] nanospheres with an average particle size of 100 nm were synthesized in an isopropyl alcoholwater medium by a solvothermal method. Then, through radical graft copolymerization of thermo-sensitive mono- mer N-isopropylacrylamide （NIPAm） and hydrophilic monomer acrylic acid （AA） onto the surface of P（MMA- St） nanospheres at 80 ℃, a series of thermo-sensitive polymer nanospheres, named SD-SEAL with different lower critical solution temperatures （LCST）, were prepared by adjusting the mole ratio of NIPAm to AA. The products were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, thermogravimetric analysis, particle size distribution, and specific surface area analysis. The temperature-sensitive behavior was studied by light transmittance tests, while the sealing performance was investigated by pressure transmission tests with Lungmachi Formation shales. The experimental results showed that the synthesized nanoparticles are sensitive to temperature and had apparent LCST values which increased with an increase in hydrophilic monomer AA. When the temperature was higher than its LCST value, SD- SEAL played a dual role of physical plugging and chemical inhibition, slowed down pressure transmission, and reduced shale permeability remarkably. The plugged layer of shale was changed to being hydrophobic, which greatly improved the shale stability
基金Supported by the National Key Special Science and Technology Project(2016ZX05015-002)PetroChina Key Special Science and Technology Project(2016E-0104)
文摘Aimed at the disadvantages of secondary damage to oil layers caused by the conventional bull-heading water control technique, a thermo-sensitive temporary plugging agent for water control was synthesized by water solution polymerization and applied in the field with a new secondary temporary plugging technique. The optimization and performance evaluation of thermo-sensitive temporary plugging agent were carried out through laboratory experiments. The optimized formula is as follows:(6%-8%) acrylamide +(0.08%-0.12%) ammonium persulfate +(1.5%-2.0%) sepiolite +(0.5%-0.8%) polyethylene glycol diacrylate. The thermo-sensitive temporary plugging agent is suitable for formation temperatures of 70-90 ?C, it has high temporary plugging strength(5-40 k Pa), controllable degradation time(1-15 d), the apparent viscosity after degradation of less than 100 m Pa?S and the permeability recovery value of simulated cores of more than 95%. Based on the research results, secondary temporary plugging technique was used in a horizontal well in the Jidong Oilfield. After treatment, the well saw a drop of water cut to 27%, and now it has a water cut of 67%, its daily increased oil production was 4.8 t, and the cumulative oil increment was 750 t, demonstrating that the technique worked well in controlling water production and increasing oil production.
基金supported by the Natural Science Foundation of Hebei Province,China(Grant Nos.E2013203296 and E2017203029)
文摘Photoanodic properties greatly determine the overall performance of quantum-dot-sensitized solar cells（QDSCs）. In the present report, the microdynamic behaviors of carriers in the nanocomposite thin-film, a Zn Se QD-sensitized mesoporous La-doped nano-TiO2 thin-film, as a potential candidate for photoanode, are probed via nanosecond transient photovoltaic（TPV） spectroscopy. The results confirm that the L-Cys ligand has a dual function serving as a stabilizer and molecular linker. Large quantities of interface states are located at the energy level with a photoelectric threshold of1.58 eV and a quantum well（QW） depth of 0.67 eV. This QW depth is approximately 0.14 eV deeper than the depth of QW buried in the Zn Se QDs, and a deeper QW results in a higher quantum confinement energy. A strong quantum confinement effect of the interface state may be responsible for the excellent TPV characteristics of the photoanode. For example, the peak intensity of the TPV response of the QD-sensitized thin-film lasts a long time, from 9.40 × 10^（-7） s to 2.96 × 10^（-4） s,and the end time of the PTV response of the QD-sensitized thin-film is extended by approximately an order of magnitude compared with those of the TiO2 substrate and the QDs. The TPV characteristics of the QD-sensitized thin-film change from p-type to n-type for the QDs before and after sensitizing. These properties strongly depend on the extended diffusion length of the photogenerated carries and the reduced recombination rate of photogenerated electron-hole pairs, resulting in prolonged carrier lifetime and an increased level of electron injection into the TiO2 thin-film substrate.
