Fatalities in the Oil and Gas Extraction Industry (FOG)
Key FOG Variable Descriptions
The FOG database collects several different types of information (i.e., variables) on each fatal incident and each worker who died in the incident. Variables about the incident are those that would be common to all fatalities associated with the incident, such as the date the event occurred and the location of the incident. Other variables are specific to each fatally injured worker, such as the worker’s age, years of experience, and cause of the fatality.
Below are the definitions for key FOG variables; these are the most commonly reported variables in FOG datasets, publications, and products.
Incident level variables: Phase of Operation
Operations are distinct stages or processes in oil and gas extraction. In FOG, each incident is assigned one operation. In instances where more than one operation is occurring, precedence will be given to the operation that primarily contributed to the fatal event. In some cases, it may not be possible to identify the operation due to the limitations of available data.
The definition of each FOG operation is below. Note: The definition does not include the explanation of technical terms (see Resources for this information).
Phase of Operation
Includes all activities related to installing casing. This includes transportation of casing, equipment, and personnel, running casing (e.g., conductor pipe, liner string, surface casing, intermediate casing, and production casing), installing casing tools (e.g., casing running tool) and accessories (e.g., centralizers, scratchers, guide shoe, float collars, and bottom and top plugs), cementing of casing, and circulating of drilling fluid through the casing. Excluded is the repair of casing and liners after installation (see Well Servicing, Intervention, or Workover.)
Includes all activities related to drilling the wellbore. This includes transportation, operation, and maintenance of the drilling rig and equipment, rig up and down, mud mixing and pumping, drilling ahead, tripping pipe in or out, coring, logging activities, and drill stem testing. Excluded is casing installation (see Casing Installation).
Includes all activities related to controlling an emergency. Generally, these activities are carried out by companies specializing in these operations. Control of a blowout, leak, or other catastrophic events, remediation, and cleanup are examples of activities included in this operation.
Includes all activities related to land and geophysical surveying to determine locations for drilling and well development.
Includes all activities related to plugging and abandoning a well after it reaches the end of its useful life. This includes removal of production equipment (e.g., separators, wellhead, tanks, pumping unit, vapor recovery, and combustion equipment, etc.), removal and salvage of the casing, placing of cement plugs, and reclamation and remediation of the site.
Includes all activities related to managing the well during production. This includes the operation and maintenance of tanks and production equipment (separator or heater treater, vapor recovery equipment, flowlines, etc.) and monitoring, storage, and transportation of production and waste fluids. Excluded are well-servicing activities (see Well Servicing, Intervention, or Workover.)
Includes all wellsite activities related to the initial preparation of the wellsite. This includes leveling, access road construction, installation of boards, matting, or gravel, excavation or trenching of the reserve pit or cellar, and installation of wellsite water supply. Also included are activities related to drilling, setting, and cementing of the conductor hole (spudding in), rathole, or mousehole.
Includes all activities where the operation cannot be determined from the available FOG data sources.
Includes all activities that occur off the wellsite, excluding roadways, where the operation cannot be determined from available FOG data sources.
Includes all activities that occur on a roadway where the operation cannot be determined from available FOG data sources.
Includes all wellsite activities where the operation cannot be determined from available FOG data sources.
Includes all activities related to the treatment and disposal of oil and gas extraction waste fluids. On-wellsite and off-site treatment of waste, disposal of waste through an injection well, and off-wellsite storage of waste are examples of activities conducted during this operation. Excluded is the on-wellsite storage and transportation of waste.
Includes all activities related to flowback operations. This includes transportation, installation, operation, monitoring, maintenance, and dismantling of flowback equipment (separators, choke manifold, flow lines, tanks, etc.), well testing during the flowback stage, plug drill out, and monitoring, storage, and transportation of flowback fluids.
Includes all activities related to hydraulic fracturing. This includes transportation, installation, operation, monitoring, maintenance, and dismantling of hydraulic fracturing equipment, perforating, fracturing fluid (base fluid, proppant, and chemical additives) blending and pumping, and zone isolations. Excluded are activities related to flowback (see Well Completion: Flowback) or other well completions activities (see Well Completion: Other).
Includes activities and methods to prepare the well for production after it has been drilled. This includes Installation of production tubing and well surface equipment (wellhead, pumping unit, christmas tree, etc.), perforating, setting packers, and techniques to begin flow (well cleanout, pumping of high-pressure gas, acidization, etc.).
Includes all activities performed on the well after it has been completed, including maintenance, remedial treatments, alterations, repairs, assessment of well or reservoir performance, and well recompletion. This includes service and workover rig activities, snubbing, swabbing, well cleanout, repair or replacement of tubing, rods, casing, or other downhole equipment, secondary cementing, and maintenance of well surface equipment such as the wellhead, christmas tree, and pumping unit.
Includes all activities that occur off wellsite at equipment yards, shops, etc. This includes equipment loading and unloading, off wellsite repair, maintenance, refurbishment, and cleaning of equipment, rigs, tanks, etc.