Selection and application of analysis methods of inorganic anion and cation content in oil and gas field water

The oil and gas field water analysis project is complex and has many analysis methods. It is mainly divided into traditional chemical analysis and instrumental analysis. The traditional chemical analysis includes titration method, gravimetric method and calculation method, which are cumbersome in steps and long time in period. And the titration end point is difficult to recognize because of the dark color of some water samples and many other interference factors. All these increase the error of experiment results. Instrumental analysis includes ion chromatography, spectroscopy and automatic potentiometric titration. Compared with traditional chemical analysis, the instrumental analysis method is faster and more accurate, but large-scale instruments and the gas cylinders are not easy to carry on-site tests. In order to ensure the accuracy of data measured by different methods, the advantages and disadvantages of each analysis method and the compatibility of each method are discussed in detail. The experiment result shows that chemical method is basically compatible with instrumental analysis method for formation water. The introduction of instrumental analysis refreshes the new understanding of formation water. The method of identifying formation water based on water analysis data provides a powerful geochemical basis for oil and gas exploration and development.