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二氧化碳驱是一种行之有效的提高采收率的技术,为设计经济可行的二氧化碳驱方案,需要对二氧化碳中的杂质气体对原油相态和驱替效果的影响进行研究。在实验基础上建立了纯二氧化碳——原油体系模型,计算不同杂质气体对该体系的相态影响;采用细管实验和状态方程方法确定最小混相压力,分析杂质气体对最小混相压力的影响;通过拟合长岩心纯二氧化碳驱替实验数据,计算了不同杂质气体对驱替过程的影响。研究结果表明,氮气和甲烷的混入不利于原油降粘和膨胀;最小混相压力随氮气和甲烷摩尔分数的增加而增加,随中间烃组分摩尔分数的增加而降低;中间烃组分能使二氧化碳的驱油效率增加,而氮气和甲烷的存在使驱油效率降低。 相似文献
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采用热蒸发法,以SiO与活性碳混合粉末为原料在1400℃的条件下制备出SiC纳米线.通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、能谱仪(EDS)及X-射线衍射分析(XRD)等手段对制备的SiC纳米线进行了表征及生长机理分析.研究表明:SiC纳米线表面光滑、平直,沿[111]方向生长,直径为30~60nm,长约数十微米,内部为约数十纳米的SiC晶体层外部约为2nm的SiO2层的异质机构.SiO作为硅源时的SiC纳米线产量高于其他硅源.最后通过光致发光(PL)光谱研究了SiC纳米线的PL特性. 相似文献
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The microstructures of vapor-grown carbon nanofibers(CNFs) before and after graphitization process were analyzed by high resolution transmission electron microscopy(HRTEM), Raman spectroscopy, X-ray diffractometry(XRD), near-edge-X-ray absorption fine structure spectroscopy(NEXAFS) and thermogravimetric analysis(TGA). The results indicate that although non-graphitized CNFs have the characteristics of higher disorder, a transformation is found in the inner layer of tube wall where graphite sheets become stiff, which demonstrates the characteristics of higher graphitization of graphitized CNFs. The defects in outer tube wall disappear because the amorphous carbon changes to perfect crystalline carbon after annealing treatment at about 2 800 ℃. TGA analysis in air indicates that graphitized CNFs have excellent oxidation resistance up to 857 ℃. And the graphitization mechanism including four stages was also proposed. 相似文献
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