Chemist, Halliburton Services, Duncan, Okla
Pages: 17 Published: Jan 1977
The method of sulfide analysis by selective ion electrode is examined, and an additional step which can be applied to all sulfide methods is described. This additional step removes interferences to the iodine titration and, at the same time, places the sample in an ideal solution for analysis. Sulfides can also be removed from slurries, such as oil field drilling muds, and analyzed by the use of the gas train. This step also helps prevent the loss of sample by volatilization and oxidation.
Comparisons of titrimetric, commercially available selective ion electrode, and Drager tube methods showed the selective ion electrode to be most reproducible and accurate. Electrode methods require fewer standardizations of solutions and eliminate dependence on visual end points. However, more sophisticated equipment is needed to utilize the precision available from electrodes. The use of Drager tubes, while found to be the most convenient method, offers less accuracy, but remains suitable for several applications. Sample pretreatment with a gas train following careful sampling methods improves the reliability of all the sulfide methods and should be included as a part of the methods.
oil fields, water injection, sulfide minerals, analysis
Paper ID: STP36568S