油田采出液中黏弹性颗粒驱油剂PPG的检测新方法

A Detection Method of Preformed Particle Gels in Produced Liquid of Oilfield

高效液相色谱法是目前检测油田采出液中聚合物含量的最简便灵敏的方法,但该方法只能对聚合物的总量进行检测。在实际应用中,为了提高驱油效率,常常会将部分水解聚丙烯酰胺HPAM和黏弹性颗粒驱油剂PPG进行复配使用,为了实现含有HPAM的油田采出液中PPG液相色谱的检测,提出了一种新的样品前处理方法,即利用HPAM和PPG结构上的差异,在样品中分别加入交联剂和破胶剂,使HPAM从溶液中沉淀出来,而PPG仍然保留在溶液中,以排除液相色谱检测PPG时HPAM的干扰。结果表明,样品中加入硝酸铝交联剂(硝酸铝、聚合物总量比=10:1)3 min后,加入破胶剂H_2O_2(H_2O_2、聚合物总量比=150:1),可以实现HPAM的完全沉淀,进而实现PPG的液相色谱检测。该方法具有很好的精确度和加标回收率,线性范围:10~200 mg/L,最低检测限为5 mg/L。

High performance liquid chromatography （HPLC） was the most simple and sensitive detection method of polymer concentration, however, HPLC can only test the total polymer concentration. In a practical application, the preformed particle gel （PPG） and partially hydrolyzed polyacrylamide （HPAM） are often used together in order to improve oil-displacement efficiency. To achieve the detection of PPG in produced liquid of oilficld （containing HPAM） using HPLC method, a new sample preparation method was put forward based on the structural differences between HPAM and PPG, the crosslinking agent and gel breaker was added into the sample, respectively, HPAM would be precipitated off, while PPG would still in the sample, resulting in that HPAM would not interfere with the detection of PPG using HPLC method. The experiment results showed that at first, AI （NO3）3 was added into the sample at the mass ratio of the Al （NO3） 3 to the total polymer of 10：1 ; after about 3 min, H202 was added into the sample at the mass ratio of H2O2 to the total polymer of 150： 1, as a result, the complete precipitation of HPAM achieved and the PPG could be detected alone using HPLC method： This method had good precision and standard addition recovery rate, the broad linear range was 10-200 mg/L, and the lowest limit of detection was 5 mg/L.