By using calcium carbonate （CaCO3） powder as the blowing agent, Al foams with porosities of - 60 to 85% and pore size of - 1.5 mm were fabricated via melt-foaming method. Instead of adding a thickening agent to incr...By using calcium carbonate （CaCO3） powder as the blowing agent, Al foams with porosities of - 60 to 85% and pore size of - 1.5 mm were fabricated via melt-foaming method. Instead of adding a thickening agent to increase Al melt viscosity, a small amount of Mg ingot （5.0 wt%） was added first, and then A1 melt was foamed by adding calcium carbonate via the impellor stirring. The effect of Mg addition on the gas release behavior of calcium carbonate in the Al melt was investigated. The compression behavior of fabricated Al foams was examined. The results show that the blowing gas is possibly from the reaction between Mg and calcium carbonate, and this reaction can produce solid oxides with micrometer level size, which leads to increasing the Al melt viscosity and is beneficial for inhibiting pores coarsening. Besides, the micrometer level cracks in the cell walls make the strength of Al foam decrease.展开更多
Triethylamine(TEA),1,4-dibromobutane(C4H8Br2)and N,N-dimethylaminopropyl acrylamide(DMAPAA)were selected to synthesize a double quaternary ammonium cationic monomer(TDD).TDD,acrylamide(AM),2-acrylamido-2-methylpropane...Triethylamine(TEA),1,4-dibromobutane(C4H8Br2)and N,N-dimethylaminopropyl acrylamide(DMAPAA)were selected to synthesize a double quaternary ammonium cationic monomer(TDD).TDD,acrylamide(AM),2-acrylamido-2-methylpropane sulfonic acid(AMPS)and acrylic acid(AA)were used to create a quadripolymer(PAAT)that was characterized by FT-IR and ^(1)H NMR.Following that,the basic performance of thickened acid was assessed.The results revealed that PAAT outperformed PAA(copolymerized by AM,AMPS and AA)in terms of acid solubility,thickening performance,temperature resistance and shear resistance.Furthermore,this crosslinked acid containing PAAT was subjected to a series of performance evaluations.The viscosity of the crosslinked acid could be kept at 67 mPa$s at 160C after 90 min and the weight loss rate of crosslinked acid in acid-rock reaction at 60 min was 23%,indicating the temperature resistance and retarder performance of the crosslinked acid solution was significantly better than that of the thickening acid and the blank acid.A scanning electron microscopy experiment revealed that crosslinked acid has good corrosion ability and low damage to the reservoir.The above experimental results indicated that the thickener PAAT has a promising future application in acid fracturing of high-temperature and high-mineralization carbonate reservoirs.展开更多
基金This work is supported by the Natural Science Foundation of Jiangsu Province of China （Grant No. BK20171437）. the Fundamental Research Funds for the Central Universities （Grant No. 2016B06614）, the Research Project of University of Science and Technology Beijing （USTB） （Grant No. 2015-Z06）. The Guiding Capi- tal lbr Industrial Development Project of Snqian and National Natural Science Foundation of China （No. 11472098）.
文摘By using calcium carbonate （CaCO3） powder as the blowing agent, Al foams with porosities of - 60 to 85% and pore size of - 1.5 mm were fabricated via melt-foaming method. Instead of adding a thickening agent to increase Al melt viscosity, a small amount of Mg ingot （5.0 wt%） was added first, and then A1 melt was foamed by adding calcium carbonate via the impellor stirring. The effect of Mg addition on the gas release behavior of calcium carbonate in the Al melt was investigated. The compression behavior of fabricated Al foams was examined. The results show that the blowing gas is possibly from the reaction between Mg and calcium carbonate, and this reaction can produce solid oxides with micrometer level size, which leads to increasing the Al melt viscosity and is beneficial for inhibiting pores coarsening. Besides, the micrometer level cracks in the cell walls make the strength of Al foam decrease.
基金The authors appreciate the financial support from the National Natural Science Foundation of China(U1762212)the Shandong Provincial Natural Science Foundation,China(ZR2019MEE037).
文摘Triethylamine(TEA),1,4-dibromobutane(C4H8Br2)and N,N-dimethylaminopropyl acrylamide(DMAPAA)were selected to synthesize a double quaternary ammonium cationic monomer(TDD).TDD,acrylamide(AM),2-acrylamido-2-methylpropane sulfonic acid(AMPS)and acrylic acid(AA)were used to create a quadripolymer(PAAT)that was characterized by FT-IR and ^(1)H NMR.Following that,the basic performance of thickened acid was assessed.The results revealed that PAAT outperformed PAA(copolymerized by AM,AMPS and AA)in terms of acid solubility,thickening performance,temperature resistance and shear resistance.Furthermore,this crosslinked acid containing PAAT was subjected to a series of performance evaluations.The viscosity of the crosslinked acid could be kept at 67 mPa$s at 160C after 90 min and the weight loss rate of crosslinked acid in acid-rock reaction at 60 min was 23%,indicating the temperature resistance and retarder performance of the crosslinked acid solution was significantly better than that of the thickening acid and the blank acid.A scanning electron microscopy experiment revealed that crosslinked acid has good corrosion ability and low damage to the reservoir.The above experimental results indicated that the thickener PAAT has a promising future application in acid fracturing of high-temperature and high-mineralization carbonate reservoirs.
