Methodology for Evaluating H<sub>2</sub>S Scavenger Performance in Crude Oil

The exploration and production of oil in Brazil are increasingly focused on deeper reservoirs and water columns, significant technological challenges related to material selection and corrosion control. The presence of H<sub>2</sub>S in crude oil undermines the integrity of industrial equipment and the quality of derived products, contributing to environmental and occupational issues that lead to heightened costs and risks associated with the operation of these industrial units. One of the solutions is the continuous injection of liquid H<sub>2</sub>S scavengers to mitigate this contaminant in industrial fluids. Testing yields important information regarding the performance of these products; however, the multitude of variables present in these tests complicates the ability to draw conclusive and reproducible observations. Furthermore, the impact of new products on subsequent processes following the injection point complicates the execution of field tests, and the careful implementation of these tests directly disrupts the normal operational and production routine. This article aims to present a detailed methodology for comparing the performance of H<sub>2</sub>S scavengers composed of different active materials in a predominantly organic medium at temperatures reaching up to 130°C, conditions resembling those encountered at the onset of production from new oil-producing wells with water content of less than 1 %(v/v). Consequently, the methodologies described allow for the assessment, comparison, and differentiation of the H2S scavenging capacity of various commercial H<sub>2</sub>S scavengers used in the oil industry, enabling their classification according to efficiency. Additionally, it consolidates in single test conditions that are closer to field application and capable of evaluating mixtures of water and oil in proportions ranging from 0 to 100 %(v/v), aqueous solutions with salinity up to 200 g/L in NaCl, temperatures between 30°C and 250°C, and pressures from atmospheric pressure up to 1034 kPa. The methodology allowed for obtaining, in addition to information on H<sub>2</sub>S scavenging capacity, an indication of the reaction time and rate required to achieve the minimum H<sub>2</sub>S content in both gas and liquid phases, facilitating the optimization of treatment protocols in oil platforms, onshore and offshore, subsea and topside, terminals, tanks, and pipelines. Among the commercial H<sub>2</sub>S scavengers evaluated in this study, the one based on ethoxylated compounds (ETO-C) demonstrated superior performance compared to the MEA-triazine-based product (TRI-C) under the same experimental conditions.