降低油田采出水配制聚合物溶液黏度损失的曝氧调控方法

Viscosity Loss Control Mechanism of Polymer Solution Prepared by Produced Water with Aeration Process

王志华 于雪莹 李杰训 乐昕朋

WANG Zhihua YU Xueying LI Jiexun LE Xinpeng

在传统以混凝除油、过滤除杂为主要技术的处理工艺基础上，对采出水回注前进行曝氧处理以降低所配制聚合物溶液的黏度损失，已成为三次采油聚合物驱地面工程的一项重要工作。为建立科学的采出水曝氧程度评价方法，规范了采出水曝氧前、后水质溶氧量的普适性测试方法，研究了水质溶氧量和采出水曝氧后矿场配注流动工况对聚合物溶液黏度、抗剪切性和黏弹性的影响。研究结果表明，溶氧管比色法需根据采出水曝氧前后溶氧量的范围选择合适的测氧管，而电化学探头法在通用性和解析度方面更具优势，可优先选择；随着采出水曝氧程度的增加，聚合物溶液的黏度提高，采出水的溶氧量从曝氧前的0.25 mg/L增至9.42 mg/L时，聚合物溶液的黏度增幅为14.88%～19.16%，聚合物溶液浓度越大，黏度损失的控制效果越显著；抗剪切性能和弹性行为也明显改善，采出水曝氧后流动工况（流速和流动沿程距离）对聚合物溶液的黏度、抗剪切性和黏弹性的影响较小；用大庆油田污水站采出水配制聚合物溶液的水质初始最佳溶氧量约为6 mg/L。研究结果从定性到定量科学化构建 了降低聚合物溶液黏度损失的油田采出水曝氧调控方法。图14 表4 参16

On the base of traditional disposal methods of produced water before re-injection in oilfields，such as coagulation and filter，the aeration treatment played a significant role in polymer flooding. In order to establish scientific evaluation method of aeration level in produced water，the reasonable testing method of the dissolved oxygen（DO）was proposed，the relationship between DO and viscosity of polymer solutions prepared by produced water was studied，and how flow conditions affected the oxygen consumption and viscoelasticity was also discussed. The results indicated that the accuracy of colorimetric method depended on the choice of testing tubes. By contrast，the electrochemical probe method performed much better during the water quality analysis. Furthermore，the viscosity of polymer solution increased with increasing aeration of produced water. After the DO in produced water increased from 0.25 to 9.42 mg/L，the viscosity increment could reach 14.88%—19.16%，shear resistance and viscoelasticity of the polymer solutions prepared by the water were also improved in a certain degree. It was obviously that the control of viscosity loss was strengthened when the solution concentration increased. However，the viscoelasticity of polymer solutions was scarcely influenced by the flow conditions of produced water after aeration. The optimum DO in water was about 6 mg/L when the polymer solution was prepared by the produced water in sewage station of Daqing oilfield. The results realized the perfect understanding of the aeration control mechanism from qualitative to quantitative.

10.19346./j.cnki.1000-4092.2017.01.029