Hydrogen Sulfide is a chemical compound, known as H2S. It is a colorless, explosive, flammable, highly toxic and very poisonous gas. It may exist in the oil and gas reservoirs, sewage and septic pits, fishing industry and farming. Since H2S is slightly heavier than air, it tends to accumulate in the low-lying and poorly ventilated spaces. H2S smells like rotten eggs in low concentrations (<100 ppm), but in high concentrations (>100 ppm), it quickly disables the sense of smell.
Effects of H2S
In case of inhalation the H2S gas, it goes directly into the lungs, reacts with the hemoglobin and reduces the oxygen’s supply of body. To neutralize the H2S effects, body breaks down the H2S into a harmless compound. If the person inhales high amount of H2S, body cannot oxidize it, so the concentration of H2S in the blood increases and it may suddenly cause loss of consciousness or death.
H2S in Petroleum Industry
Since hydrogen sulfide is an inseparable parts of sour gas in the reservoir, it is commonly encountered during different drilling and production operations such as drilling, well testing, work over and production. Long-term exposure to the low-concentration or short-term exposure to the high-concentration of H2S may cause irreversible damages to health of personnel working in that environment. So the proper prevention and mitigation measures should be taken to provide protection against any damages.
H2S Safety in Oil and Gas Industry
H2S safety considerations in Oil and Gas Industry are classified into two main categories including safety training and safety equipment based on prevention and mitigation measures.
H2S Safety Training
H2S safety training is divided into two parts. First part is training the H2S officers and the second one is training all persons working at the wellsite. Training the H2S officers includes theoretical instructions like the certified training courses approved by certified institutes and practical training such as equipment inspection, testing and maintenance services. Training the personnel consists of H2S safety courses, delivered by certified safety institutes and should be passed before first entrance to the wellsite, and induction training at the wellsite like briefing muster points, emergency evacuation routes and proper way of using SCBA. Weekly H2S drill should be held by H2S officer, HSE officer and wellsite manager to make sure that every single person at the wellsite is ready to follow the H2S safety instructions in an emergency situation.
H2S Safety Equipment
- Grade “D” Standard based breathing air
- Air compressors with carbon monoxide detectors
- Low-pressure manifolds
- Onsite respiratory PFT and fit testing
- 2, 6, 8 and 12-cylinder breathing air cascades
- Advanced wireless H2S/LEL gas detection sensors
- Mobile H2S/LEL gas detectors
- Multi-channel control systems for H2S/LEL combustible sensors
- Hazardous location visible and audible alarms
- Gas calibration kits for H2S/LEL, SO2, NH3, CO2 and CO gases
- Self-contained breathing apparatus (SCBA)
- Tailor-made H2S safety response packages