The occupational exposure risk of chemicals to personnel during well construction operations is managed and controlled. The control of exposure of personnel to chemicals during well construction operations has not always been given the same focus as environmental issues. To some extent the reduction of environmental risks has also resulted in reduced health and safety risks. The containment of fluids for disposal, rather than immediate discharge may increase occupational exposure. It is important to conduct comprehensive risk assessments of drilling fluid systems that consider health, environmental and safety issues.
A significant quantity of the chemicals supplied to the well site are used during drilling operations. As a result, drilling operations give rise to the greatest occupational exposure to drilling fluids. In this paper the general background of drilling fluids and the various categories of base fluids and additives in use today are discussed. The paper examines trends in use, human exposure, best practices in fluid use, monitoring of health hazards and effects, and recommends some risk reduction measures.