Purpose of the paper is to review environmental aspects of Oil & Gas drilling in view of economics of the projects benefiting industry professionals. Oil & Gas exploration, including offshore & directional drilling pose long and short-term environmental risks. These risks are primarily associated with (a) contamination due to drilling wastes (muds, produced waters, byproducts, etc.); emissions from drilling sites and potential runoffs, (b) natural gas/oil leaks and spills, and (c) direct effects on human health. The drilling fluids circulated through the well hole contain toxic materials (including oil/grease, arsenic, chromium, cadmium, lead, mercury, & naturally occurring radioactive materials). The composition of drilling muds and produced waters varies widely depending on location & depth of well; and type of drilling fluid. Produced waters potentially impacting the surface or groundwater are typically disposed of in a deep aquifer, but there is still the threat of accidental release from temporary storage. Contributing to air pollution are also the potential emissions of hydrogen sulfide present in natural gas deposits. Its short & long-term direct effect on human health could be severe, from unconsciousness to death within a few breaths. Statistically, 0.5-1% of exploratory wells result in blowout, causing harmful emissions. Additionally, pressurized contents of a geologic formation literally explode out of the new well, severely impacting environment and the project economics.
The paper includes summary statistics of environmental incidences, their causes & preventions based on actual projects. The accidents are related to well drilling, pipelines incidents and spills/leaks listed by cause (equipment failure, corrosion, joints, materials, etc.).
Paper presents guidelines and economically feasible options to minimize risks to environment & human health. It also provides an overview of the environmental concerns, project economics and sustainability issues.