双河油田提高聚合物驱高温稳定性的方法研究

Study on the Methods of Improving the High Temperature Stability of Polymer Flooding in Shuanghe Oilfield

黎锡瑜

LI Xiyu

为提高双河油田高温油藏聚合物驱的稳定性，用普通部分水解聚丙烯酰胺（HPAM）和油田污水配制聚合物溶液，在95℃条件下研究了自由基氧降解、水解作用对HPAM溶液黏度的影响，分析了双河油田高温油藏聚合物降解的主要机理，讨论了几种有效提高HPAM高温热稳定性的方法。结果表明，溶解氧会导致HPAM溶液黏度大幅下降：当溶液中氧含量由0.5 增至3.0 mg/L 时，聚合物溶液在95℃老化180 d 的黏度保留率由100%降至27.5%。HPAM的高温水解速度很快，但在溶液氧含量小于0.3 mg/L和HPAM水解度为40%～60%时，溶液黏度无明显下降。自由基降解是双河油田高温油藏聚合物降解的主要机理，控制氧含量、抑制聚合物自由基降解是提高聚合物稳定性的技术关键。在80～95℃油藏，采取无氧配注与新型聚合物驱技术，或在HPAM溶液中加入少量交联剂形成低度交联聚合物溶液，可以明显提高聚合物的耐温性能，取得良好的矿场应用效果。图4表2参12

In order to improve the stability of polymer flooding in high temperature reservoir of Shuanghe oilfield，ordinary partially hydrolyzed polyacrylamide（HPAM）mixed with oilfield produced water were chosen to study the influence of thermal oxidation degradation and hydrolysis on the viscosity of HPAM solution at 95℃. The main mechanism of polymer degradation in high temperature reservoir of Shuanghe oilfield was analyzed and several methods to improve HPAM thermal stability were discussed. The results showed that the existence of dissolved oxygen would sharply lower the viscosity of HPAM solution. When the oxygen content increased from 0.5 to 3.0 mg/L，the viscosity retention rate of HPAM solution decreased from 100% to 27.5% after aging 180 d at 95℃. The hydrolysis rate of HPAM was very fast at high temperature. While the viscosity of HPAM solution was not significantly decreased when the degree of hydrolysis was 40%—60% and the oxygen content was less than 0.3 mg/L. The free radical degradation was the main mechanism of polymer degradation in high temperature reservoir of Shuanghe oilfield. Controlling oxygen content and inhibiting free radical degradation of HPAM were the key technology to enhance the stability of HPAM at high temperature. When the polymer was applied in reservoir with 80—95℃ ，taking oxygen control technology at the process of polymer preparation and new type of polymer flooding technology，or adding a small amount of cross-linking agent in HPAM solution to form low crosslinked polymer solution could significantly improve the heat resistance of polymer，which obtained good oil displacement results in field application.

10.19346./j.cnki.1000-4092.2017.04.019