液相色谱法测定油井采出液中HPAM浓度的制约因素

Restriction Factors of Concentration Determination of Partially Hydrolyzed Polyacrylamide in Oil-well Produced Fluid by Liquid Chromatography

为提高液相色谱法测定采出液中部分水解聚丙烯酰胺(HPAM)浓度的准确度,研究了聚合物相对分子质量、分子量分布、水解度和溶液矿化度等因素对测定结果的影响,分析了现场采出液聚合物浓度测定中存在的问题。结果表明,聚合物的相对分子质量、分子量分布及矿化度对浓度测定结果无明显影响;水解度是液相色谱法测定采出液中聚合物浓度的制约因素,随着聚合物水解度的增加,工作曲线的斜率增大,当标样的水解度低于待测样品时,测定结果偏低;反之,则偏高。用合适孔径的微孔滤膜结合蒸馏水稀释的方法对现场待测样品进行预处理,可以排除采出液样品含油、有机杂质和色度高等干扰因素的影响;在现场测定时,以注入的聚合物干粉样品作为标样,聚合物浓度的测定结果低于实际值。

In order to improve the determination accuracy of partially hydrolyzed polyacrylamide （HPAM） in produced liquid by liquid chromatography, the effect of HPAM relative molecular weight, molecular weight distribution, hydrolysis degree, solution salinity and other factors on the determination results was studied, and the problems existing in the determination of HPAM concentration in produced fluid on site was analyzed. The results showed that the polymer relative molecular weight, molecular weight distribution and solution salinity had no significant impact on the concentration determination, while the hydrolysis degree was the restriction factor of polymer concentration determination in produced fluid by liquid chromatography. The slope of work curve increased with increasing hydrolysis degree of HPAM. When the hydrolysis degree of standard sample was lower than that of the sample to be tested, the measured result was lower than the true one, on the contrary, that was higher. After tested sample on site was pretreated by microporous membrane with suitable pore size and dilution method with distilled water, the interference effect of the oil in produced fluid sample, organic impurities and higher chromaticity could be eliminated. Because the polymer dry powder sample for injection as standard sample on site measurement, the measured result of polymer concentration was lower than the actual value.