油田污水中硫化亚铁含量的测定方法探讨

方培林，廖 粤

(中海油（天津）油田化工有限公司;天津 300452)

摘 要：海上某油田水处理系统含硫化亚铁导致水体发黑，流程管线结垢堵塞。通过对堵塞物样品成分分析发现，堵塞物主要成分为硫化亚铁，为稳定注水水质，减轻管线结垢，需定期检测污水中硫化亚铁含量，评估铁离子稳定剂或水质稳定剂的处理效果。本文探讨了一种紫外可见分光光度计测污水中硫化亚铁含量的方法，以抗坏血酸钠为还原剂，在避光条件下测定油田污水中硫化亚铁的浓度。以蒸馏水为参比溶液，在288nm处测量污水吸光度。根据实验结果得到线性回归方程:Y=0.0541X,R=0.9955。相对于传统硫化镉沉淀法，该评价方法操作简便、可靠、重现性好，适合于含硫化亚铁污水用铁离子稳定剂与水质稳定剂的快速筛选评价。

关键词：硫化亚铁；黑水；评价方法；铁离子稳定剂；水质稳定剂；

中图分类号：TE973   文献标识码：B

Discussion on testing method of ferrous sulfide in oilfield sewage

Fang Peilin

(CNOOC (Tianjin) Oilfield Chemical Ltd.; Tianjin 300452)

Abstract： The content of ferrous sulfide in the water treatment system of an offshore oilfield can cause water becoming black and scale blockage in pipeline. Through the analysis of scale sample composition, it is found that the main component of scale sample is ferrous sulfide. In order to stabilize the water quality of injection water and reduce the scale in pipeline, the content of ferrous sulfide in sewage should be tested regularly. The effection of ferrous ion stabilizer or water stabilizer was evaluated by measuring the content of ferrous sulfide. This paper discusses a method for determination of ferrous sulfide in sewage by ultraviolet visible spectrophotometry. Using sodium ascorbate as reducing agent, the concentration of ferrous sulfide in oilfield sewage is determined under the condition of avoiding light. The absorbance of sewage was measured at 288nm using distilled water as reference solution. According to the experimental results, the linear regression equation is obtained :Y=0.0541X,R=0.9955. Compared with the traditional cadmium sulfide precipitation method, the method is simple, reliable and reproducible, which is suitable for the rapid screening and evaluation of iron ion stabilizers and water quality stabilizers for ferrous sulfide wastewater.

Keywords：Ferrous sulfide; Black water; Evaluation Method; Ferrous ion stabilizer; Water stabilizer

1 引言

海上某油田由于含一定量的硫化氢气体与硫酸盐还原细菌，硫酸盐还原菌的大量繁殖导致的微生物腐蚀会产生亚铁离子，生产污水中的硫离子与铁离子反应生成硫化亚铁，由于硫化亚铁溶解度极低，25℃时硫化亚铁溶度积为6.3×10-18，容易形成硫化亚铁颗粒析出，其悬浮于水中，造成水处理系统出现“黑水”现象，硫化亚铁的形成一方面会导致污水悬浮物含量升高，悬浮物以硫化亚铁垢形式沉积堵塞过滤系统、地面流程管线与井下注水管柱^[1]，参见图1。另一方面，由于硫化亚铁颗粒具有油水双润湿性，会吸附在油珠表面阻碍油珠聚并，导致污水含油升高[2]。对该平台平台水力旋流器堵塞物垢样成分分析发现，垢样有机物含量23.4%，无机物含量76.6%，其中无机物主要成分为硫化亚铁，含量为50.8%，分析结果见表1。

（方培林）油田污水中硫化亚铁含量的测定方法探讨.pdf