A油田注入水水质变化原因分析及稳定对策

Injection water quality changes and countermeasures for stability of A oilfield

梁金禄 王荣健 黄小玉 石海信 2

北部湾大学石油与化工学院，广西 钦州 535011 广西省北部湾海洋灾害研究重点实验室，广西 钦州 535011

College of Petroleum and Chemical Engineering, Beibu Gulf University, Qinzhou 535011, China Guangxi Key Laboratory of Marine Disaster in the Beibu Gulf, Qinzhou 535011, China

海上A油田注入水经过精细过滤后，水质变浑浊，且对岩心的堵塞比较严重，不能满足回注要求。因此，室内通过测定离子组成、浊度值、溶解氧质量浓度、细菌数量等水质指标以及浑浊物成分，分析注入水水质变化的原因。结果表明：注入水中溶解氧质量浓度的增大导致细菌大量繁殖是造成水质变浑浊的主要原因。通过除氧剂以及杀菌剂的优选实验，研究了适合该油田注入水的水质稳定措施，在注入水中加入1 000 mg/L的除氧剂CYJ￣10和30 mg/L的杀菌剂SJJ-3能使水样浊度值不发生明显变化，岩心驱替100 PV后的渗透率保持率大于85%。现场应用结果表明，采用水质稳定措施后，注入水水质未发生明显改变，M井的注入量能够保持较长时间的稳定，增注效果良好。

The injected water of offshore A oilfield becomes turbid after fine filtration, and the core is blocked seriously, which cannot meet reinjection requirement. Therefore, the reasons for the change of injected water quality were analyzed by measuring the water quality indexes such as ion composition, turbidity value, dissolved oxygen concentration, bacterial content and the components of turbidity. The results show that the increase of dissolved oxygen content in the injected water leads to bacterial mass propagation, which is the main cause of water turbidity. Through the optimization experiment of deoxidizer and bactericide, the water quality stabilization measures suitable for the oilfield injected water were studied. The water sample turbidity value cannot be significantly increased by adding 1,000 mg/L deoxidizer CJY-10 and 30 mg/L bactericide SJJ-3 into the injected water, and the retention rate of permeability after core displacement of 100 PV is more than 85%. The field application results show that after adopting the water quality stabilization measures, no water quality denaturation is found in the injected water. The injected quantity of M well can keep stable for a long time, and good injection increase effect has been achieved.