Protection against overexposure to H2S, a highly toxic and explosive gas, starts with understanding the chemical and the inherent risks it carries. Specifically to the petroleum industry, although, it’s not the only industry susceptible to the danger.
The colourless gas (known as a sour gas) is naturally produced by the decomposition of organic materials, including oil and gas deposits. It’s also emitted as a by-product of many industrial processes, including the desulfurisation process, involved in petroleum production and refining.
The main cause of exposure to H2S is through inhalation of the gas. It is absorbed through the lungs, making it fatal to workers. People can only smell the “rotten egg” odour when lower concentrations of the gas are present. However, after continuous low-level exposure, or higher concentrations, you could lose your sense of smell to the gas quite quickly.
H2S is a major hazard to workers in the oil and gas industry
During drilling operations, H2S can be released through the shale shaker and circulation fluid treatment areas. Additionally, it can be from tripping procedures, at the wellhead, in the cellar, and onto the drilling floor. In these confined space areas, the chemical can build up to dangerous levels. For example, in low-lying areas like trenches, pockets of H2S can form, leaving little space for escape.
Since gas can be present in these underground areas, workers should be properly trained before they enter and work in these types of conditions. The operational crew should be prepared to use proper protection and personal protective equipment (PPE) when working in H2S-prone areas. H2S enters drilling mud from subsurface formations and can also be produced by sulfate-reducing bacteria in stored muds. The presence of H2S can also lead to sulfide stress corrosion, which can crack the metal. This can compromise the underground tubing and casing, which leads to other safety and costly equipment issues.