埕东油田泡沫复合驱先导试验污水对聚合物溶液黏度影响因素研究

Effect of sewage on polymer solution viscosity: Pilot test of foam combination flooding in Chengdong Oilfield

油田污水配制聚合物易导致聚合物溶液黏度大幅度降低,严重影响了聚合物的应用效率和采油效果。以埕东油田泡沫复合驱先导试验区为基础,通过对油藏地质、地面流程及污水水质等系统的测试分析,开展了油田污水配制聚合物导致黏度损失严重的影响因素的研究。研究结果表明,聚合物溶液黏度损失主要发生在聚合物母液(清水配制)与污水混合处,主要原因是污水中的还原性物质与溶解氧在痕量金属离子的作用下发生氧化还原反应导致聚合物断链,黏度急剧下降。使用在污水与聚合物母液接触之前消除或最大程度减小污水中还原性物质及痕量金属离子的方法,可以降低对聚合物溶液的降黏影响。研究结果对于保证现场矿场的注聚质量和效果具有指导作用。

Polymer solution prepared by Oilfield sewage resulted in significant viscosity reduction, influencing the application efficiency and oil recovery effect seriously. Based on the foam combination flooding test in Chengdong Oilfield and the analysis of reservoir geology, surface flow and sewage quality, a study was conducted about effect of sewage on polymer solution viscosity. The results showed that the viscosity loss of polymer solution mainly occurred when polymer mother liquid mixing with sewage. The main reason was that the redox reaction of reducing substance in sewage and dissolved oxygen occurred when trace metal ions were present, which caused polymer chain scission, and a sharp drop of viscosity. The main countermove is to eliminate or decrease the reducing substance and trace metallic ions before the sewage contacts with polymer mother liquid. The results can be used to guarantee the quality and effect of field polymer injection.