稀释水对注入体系黏度影响分析及对策

Analysis and Countermeasures of the Effect of Diluted Water on the Viscosity of the In⁃jection System

X区块因清污平衡需要,采用“清配污稀”配注方式,稀释水中还原性物质含量在工艺节点有较大变化,是降低注入体系黏度的关键。针对污水稀释聚合物工艺中还原性物质种类及溶解氧对聚合物注入体系性能影响开展研究,通过现场调研、室内实验、菌以及化学元素的检测分析、现场试验等多种研究途径,摸索出污水合理曝氧量及经济有效的治理措施。分析认为影响聚合物溶液黏度的主要还原性物质为Fe^(2+)和S^(2-),是油田污水中SRB的代谢产物,从而明确了黏损治理的主要方向;生产数据表明水处理过程中污水溶氧量较大时,能去除大部分二价铁和硫化物,但回注前仍需进行杀菌处理和曝氧处理;剩余氧含量大于5 mg/L时能较好抑制还原性物质的含量;定期冲洗单井管道和母液管道,能改善水质、降低SRB菌含量、减少腐蚀,降低黏损2.4个百分点以上,最终实现产能区块的高效开发。

Due to the need to ensure a balance between clean water and sewage,Block X mainly adopts the method of"clean water preparation and sewage dilution".The content of reducing substances in diluted water varies significantly at process nodes,which is the key to reducing the viscosity of the injection system.A study is conducted on the effects of reducing substances and dissolved oxygen on the performance of polymer injection systems in sewage diluting polymer processes.Through various research methods such as on-site investigation,indoor experiments,detection and analysis of bacteria and chemical elements,and on-site experiments,reasonable oxygen exposure and economically effective treatment measures for sewage are explored.Analysis suggests that the main reducing substances that affect the viscosity of polymer solutions are Fe^(2+)and S^(2-),which are metabolic products of SRB in oilfield sewage,thus clarifying the main direction of viscosity loss control.The production data shows that when the DO content in sewage is high during water treatment process,most of the divalent iron and sulfides can be removed,but sterilization and oxygen exposure treatment are still required before reinjection.When the residual oxygen content is greater than 5 mg/L,it can effectively inhibit the content of reducing substances.Regular flushing of single well pipelines and mother liquor pipelines can improve water quality,reduce SRB bacterial content,reduce corrosion,reduce viscosity loss by more than 2.4 percentage points,and ultimately achieve efficient development of production capacity blocks.