Abstract：The high salinity formation water produced by the production gas well corrodes the pipeline,has major potential safety hazards,and affects the normal production of the gas well.Continuous iron ion concentration detection is a common method to monitor the corrosion of produced water on the production gas well pipeline and evaluate the effect of corrosion prevention and control measures.Due to the mixing of formation debris,working fluid residue,foaming agent added in the production process of gas well and produced water,the composition of gas well wastewater is complex and the turbidity is high.The detection result of iron ion concentration in gas well wastewater by spectrophotometry is relatively uncertain and has a wide range of fluctuation.Based on the five elements of man, machine,material,method and environment,this paper carries out detailed experimental analysis and demonstration.Combined with the experimental data,it is determined that the sampling method,sample aging method and sample turbidity control are the three main factors affecting the relative uncertainty of iron ion concentration detection of gas well wastewater,and it is proposed that "sampling after mechanical mixing and heating in 100 ℃ water bath for 30 min to promote the full reaction of the sample,0.45 μm filter membrane suction filtration to control turbidity.The relative uncertainty range of iron ion concentration detection in gas well wastewater is reduced to less than 15%,which meets the needs of produced water pipeline corrosion monitoring,and provides reliable data support for the formulation of "one well,one policy" refined prevention and control measures.
2023, Vol. 33 