浊度控制法处理油田产出水技术研究与应用

A Recycled Produced Water Treating Technology by Using Turbidity Control

根据现场水质监测数据,靖安油田五里湾作业区油田产出水含油量、悬浮物、浊度高且不稳定,腐蚀性大,细菌含量高。采用稀释倍数法对一个水样进行检测,发现浊度〈2 NTU时含油量、悬浮物均达到回注水标准（〈5 mg/L）。以浊度作控制指标筛选了各种净水剂及适宜用量：pH调节剂NaC lO＋NaOH,40 mg/L;无机絮凝剂PAC,50mg/L;有机絮凝剂PAM（M=1.2×10^7）,2 mg/L,这一组净水剂用于处理浊度为150±20 NTU的产出水时,加药量最稳定。提出了浊度控制法处理油田回注污水工艺并用于日处理水量1200 m3的该作业区回注污水处理站,处理程度包括：浊度控制130－170 NTU,加剂絮凝沉降、二级过滤,滤前加杀菌剂,滤后加缓蚀剂、阻垢剂,处理后水悬浮物、含油量、细菌SRB和TGB、浊度、腐蚀速率均达到注水标准。

It was shown by field water quality monitoring data that the produced water（PW） in Wuliwan district of Jing＇an oil field was characterized by high and changeable oil content（OC）,suspended solids（SS）,and turbidity,high bacteria content,and severe corrosivity.Through investigating a PW sample by the way of dilution,it was found that the OC and SS values of the PW might meet the requirements for flooding waters if the turbidity was 〈2 NTU.With turbidity taken as a crioterion,water treating agents were screened and their dosages optimized：pH regulator NaClO＋NaOH in mixture,40 mg/L;inorganic floccutant PAC,50 mg/L;organic floccutant PAM of M=1.2×10^7,2 mg/L.The dosages of this set of chemicals needed for treating the PW of turbidity of 150±20 NTU were the lest changeable.A PW treating technology based on turbidity controll was suggested and applied in Wuliwan recycled produced water treating plant of output 1200 m^3/d,covering following stages：adjustment of the turbidity of the PW to be treated in range 130—170 NTU;chemical coagulation/flocculation;two-stage filtration with bactericide introduced before and corrosion and scale inhibitors——after filtration.The PW treated met the requirements to flooding waters in SS,OC,SRB and TGB bacterial population,turbidity,and corrosivity.