油田采出水中可溶性硫化物测定方法

Determination method for dissolvable sulfide in oilfields produced water

采用电位滴定法测定油田采出水中可溶性硫化物，优化了分析操作条件，分析了油田水质因素对测定的影响及干扰消除方法，并对油田采出水实际水样进行了分析测定．结果表明，测定时溶液pH值应大于12．0，至少10倍于硫离子质量浓度的无机阴阳离子、含油量、悬浮固体、聚合物和表活剂对测定不产生影响。取样时加入硫化物稳定剂可消除水中氧的影响．方法的精密度小于5．0％，加标回收率在93．0％～107．0％之间，方法检测下限为0．3mg／L．对大庆油田实际水样分析表明，油田各个产能区的油田采出水中均不同程度含有可溶性硫化物．单个样品分析时间少于10min．

Determining the dissolvable sulfide in oilfield produced water by potentiometric titration method, this paper optimizes the analytic and operational conditions, analyzes the influences of oilfield water-quality on determination as well as the disturbance eliminating method, and proceeded analysis and determination on the actual sample of oilfield produced water. The results show that it has no influences on determination when the pH value is above 12.0 and the concentration of inorganic zwitterions, oil content, suspended solid, polymers and surfactant are more than 10 times of sulfide ion concentration. Adding sulfide stabilizers in sampling time can eliminate the disturbance from oxygen in water. The precision of this method is within 5.0% ,the recovery of standard addition is between 93.0% - 107.0%, and the detection limit is 0.3 mg/L. The results of analyzing the actual sample of Daqing oilfield produced water show that dissolvable sulfide is contained in oilfield produced water in every productivity area. The analyzing time of every sample is within 10 min.