New application for Micromax in aqueous drilling fluids as a hydrogen sulfide scavenger

Abstract

The release of hydrogen sulfide (H2S) during drilling operations endangers workers' health and safety while also causing corrosion-related equipment damage. Various H2S scavengers have been used, but researchers are still looking for an optimal and feasible scavenger. Micromax (manganese tetroxide, Mn3O4), which has high oxidation and absorption capabilities with a high manganese oxide content, may effectively scavenge H2S. This study aimed to address the potential of using Micromax as a scavenger for H2S in aqueous drilling fluid. The study investigated the impact of Micromax addition on the drilling fluid rheology, filtering behavior, alkalinity, and corrosion propensity. The experiments were performed for a base drilling fluid without scavengers and with two commercial scavengers (i.e., triazine and SourScav®), which serve as benchmarking references. The findings showed that Micromax increased the scavenging capacity of the fluid by 706.6%, which was about 4 and 5 times higher than those of triazine and SourScav, respectively. Micromax and commercial scavengers did not impair the drilling fluid's rheology, but they slightly increased the formed filter cake thickness. Micromax and triazine maintained the pH of drilling fluids at a safe level above 10, which is required in a sour environment, unlike SourScav, which reduced the pH to a critical value of 7.9. Micromax and the other two commercial scavengers demonstrated noncorrosive characteristics with nearly zero corrosion rate. For the first time, the present work demonstrated the potential application of Micromax as a low-cost H2S scavenger with competent mud properties for effective and safe drilling operations.