One of the stock-tank oil quality indicators according to requirements of regulatory documents, is content of organic chlorides in fraction that boils at temperatures range from the true boiling point to 204 °С. Main sources of oil contamination with organochlorine compounds are chemical agents used at certain stages of oil production. Numerous studies have confirmed that certain chemical agents initially free from organochlorine compounds can promote their formation. These are hydrochloric acid and quaternary ammonium salts contained in some corrosion inhibitors, bactericides, and paraffin inhibitors. Oil production is a complex process flow that involves application of both pure chemicals, and a wide variety of chemical compositions. One of the most widely used components of these compositions is hydrochloric acid, which, potentially can react with each agent in a composition. To assess the risk of formation of organochlorine compounds in the process of injection of HCl-based compositions, chemical interactions of individual components were studied. To determine the content of organic chlorine in organochlorine compounds, X-ray fluorescence analysis and gas chromatography-mass spectrometry methods were used. It was found that organochlorine compounds can be formed following reactions between chemical agents and hydrochloric acid contained in fluids used in the process of oil production; also, agents with high content of unsaturated compounds can, potentially, lead to forming of organochlorine compounds. Considering high risk of organochlorine compounds forming, such solvents are not recommended for use in technologies involving contact with hydrochloric acid.
References
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