Oil and natural gas drilling rigs are used to identify geologic reservoirs and also to create holes that allow the extraction of oil or natural gas from those reservoirs. Primarily in onshore oil and gas fields once a well has been drilled, the drilling rig will be moved off of the well and a service rig (a smaller rig) that is purpose-built for completions will be moved on to the well to get the well online.
Oil refineries, processing plants, pipelines, storage farms, LPG/LNG plants, and offshore platforms all utilize or produce a wide range of hazardous combustible and toxic gases. Furthermore, the processes involved in each can produce nontoxic gases which when amassed in high concentrations, depletes oxygen causing a hazardous condition to personnel who occupy the area without proper protection.
Oil and gas facilities can be expected to accidentally and routinely emit hydrogen sulfide in concentrations that span a wide range and are associated with a variety of health effects.
Hydrogen sulfide is a naturally occurring component of crude oil and natural gas. Petroleum oil and natural gas are the products of thermal conversion of decayed organic matter (called kerogen) that is trapped in sedimentary rocks. High-sulfur kerogens release hydrogen sulfide during decomposition, and this H2S stays trapped in the oil and gas deposits.
Hydrogen Sulfide (H2S) is a major hazard encountered at drilling sites. Leaks in drilling applications can release large quantities of H2S thus in turn can spread to nearby communicating can effect released, which becomes extremely hazardous to well-site personnel. Areas that are susceptible to leaks include the drillers stand, blow-out preventer, shale shaker and mud tank.
Methane (CH4) is the predominant component of natural gas, comprising 70 to 90 percent, while other gaseous hydrocarbons, butane (C4H10), propane (C3H8), and ethane (C2H6), account for up to 20 percent. Contaminants present in natural gas, which have to be removed at natural gas processing facilities, include water vapor, sand, oxygen, carbon dioxide, nitrogen, rare gases such as helium and neon, and hydrogen sulfide. In fact, hydrogen sulfide is the predominant impurity in natural gas. The Environmental Protection Agency (EPA) classifies natural gas as sour when H2S is present “in amounts greater than 5.7 milligrams per normal cubic meters ( mg/Nm3) ( 0.25 grains per 100 standard cubic feet )
