采出液中聚合物浓度准确测定方法及应用

Method for Accurate Determination of Polymer Concentration in Flooding-polymer Produced Fluid and its Application

胡科 张健 陈文娟 薛新生 王姗姗 朱玥珺

HU Ke ZHANG Jian CHENWenjuan XUE Xinsheng WANG Shanshan ZHU Yuejun

定氮法检测海上油田注入井聚合物浓度具有快速、准确及安全的特点，但在应用到采出液聚合物浓度检测过程中发现，采出液中乳化原油、泥砂等杂质难以分离，会导致吸光度偏大而干扰测定结果。为提高采出液中聚合物浓度测定的准确性，本文分析了采出液中乳化原油粒径分布、残余聚合物水动力学直径及相对分子量质量分布，结合微孔滤膜的筛分原理提出并规范了采出液聚合物浓度“微滤膜过滤-定氮”检测方法。研究表明，采出液乳化油珠粒径主要分布在5～20 μm之间，粒径中值9～17 μm，80%以上乳化油珠粒径大于5μm，而残余聚合物水动力学直径在0.4～1.2 μm之间，二者范围可明显区分。选用孔径尺寸为1.2～5 μm微滤膜对采出液进行预处理，可使定氮法测定采出液中聚合物浓度时的误差由16%缩小到5%以内。该检测方法经过在海上注聚油田的反复试验，取得了良好的应用效果。图10表2 参15

The offshore oil field injection well polymer concentration can be measured fast，accurately and safely by nitrogen detection technology，however，when detecting the produced fluid，it was found that the impurities including emulsified crude oil and mud sand，etc，are difficult to be separated，which lead to larger absorbance and interfere the determination results. Based on the above situation，the particle size distribution of emulsified crude oil，hydrodynamic diameter，relative molecular mass distribution，etc，was analyzed，combining the screening theory of microporous filtering film，a“microporous filtering film filternitrogen content determination”method was established to determine the polymer concentration in produced fluid. The results showed that the produced fluid oil droplet size was mainly distributed in range of 5—20 μm with median diameter of 9—17 μm， more than 80% emulsified oil droplet size was larger than 5 μm，while the residual polymer hydrodynamic diameter was mainly distributed between 0.4—1.2 μm. Based on the size difference between the oil droplet and polymer，the microporous filtering film with aperture size of 1.2—5 μm was chosen to pretreat the produced fluid，and the determination error could be reduced from 16% to 5%. The method has been tested several times in offshore polymer injection oilfield，and an excellent application effects has been obtained.

10.19346/j.cnki.1000-4092.2017.02.032