Juru Bor (Driller) key terms

The ranked order for managing a hazard: eliminate it, substitute something safer, use engineering controls, then administrative controls, and finally personal protective equipment as the last line of defence.

A structured process that identifies each hazard on a task, judges how likely and how severe the harm is, and records the controls chosen to reduce the risk to an acceptable level.

A pre-task breakdown of a job into sequential steps, with the hazards of each step listed and the specific controls agreed before work starts, usually signed off by the crew involved.

A formal written authorisation for high-risk activity such as hot work, confined space entry or lockout, stating the precautions required, the validity period and who may authorise and perform the task.

A procedure in which an energy source is isolated, locked in the safe position and tagged with the owner's name so equipment cannot be re-energised while someone is working on it.

The zoning of rig spaces by the likelihood of flammable gas or vapour being present, which determines what electrical equipment and ignition sources are permitted in each zone.

A standardised document supplied with a chemical that lists its hazards, exposure limits, handling precautions, first aid measures, spill response and disposal requirements.

A highly toxic, colourless gas that smells of rotten eggs at low levels but deadens the sense of smell, is heavier than air and can be lethal in confined or low-lying rig spaces.

The use of calibrated detectors to measure oxygen, flammable gas and toxic gas levels before entry into a space and continuously while people remain inside it.

The assembly of drill pipe, drill collars and tools that transmits rotation and weight to the bit and provides a conduit for drilling fluid from surface to the bit.

A rig system that rotates the drill string from a motor suspended in the derrick, allowing drilling of stands rather than single joints and enabling circulation while tripping.

The rotating deck equipment that turns the kelly or drill pipe through the rotary bushing and supports the string load through the master bushing and slips.

A square or hexagonal steel pipe that passes through the rotary table bushing, transmits rotation to the drill string and allows the string to slide down as the hole deepens.

A large valve stack installed at the wellhead that can close around or seal off the drill string or open hole to stop uncontrolled flow from the well.

A blowout preventer with a flexible rubber element that closes around any shape in the wellbore, sealing on drill pipe, kelly, casing or open hole.

Wedge-shaped gripping tools set in the rotary table or on the drill floor to hold the weight of the drill string when it is not supported by the elevators.

Lifting clamps attached to the travelling block that grip the drill pipe or collar by its shoulder so the string can be raised, lowered and hung off.

The liquid or gas mixture circulated down the drill string and up the annulus to cool the bit, carry cuttings, control formation pressure and stabilise the wellbore.

The density of the drilling fluid, usually expressed in pounds per gallon or kilograms per cubic metre, set to balance formation pore pressure without fracturing the rock.

The space between the outside of the drill string or casing and the wall of the open hole or the inside of the casing, through which returns flow to surface.

The pressure of fluids trapped in the pores of a formation; if mud weight is too low, formation fluid can flow into the wellbore.

The loss of drilling fluid into a permeable or fractured formation, which reduces returns, lowers the fluid level in the annulus and can lead to a kick.

The speed at which the bit advances through rock, usually measured in metres or feet per hour, and used to judge bit condition and drilling efficiency.

The portion of the drill string's weight deliberately applied to the bit to make it cut, controlled by the driller through the brake and string tension.

The rate at which the drill string is turned, expressed in revolutions per minute, and balanced against weight on bit to optimise penetration and bit life.

A condition in which the drill string can no longer be moved up, down or rotated, commonly caused by differential sticking, hole collapse, cuttings beds or key seating.

An unintended influx of formation fluid into the wellbore because the hydrostatic pressure of the mud column is lower than formation pore pressure.

The early recognition of an influx from indicators such as flow with the pumps off, pit volume gain, changed pump pressure, gas readings or a string weight change.

The deliberate closing of the blowout preventer and choke to stop flow from a well while pressures are recorded for well control decisions.

The mud density calculated to provide hydrostatic pressure slightly above formation pore pressure so the well can be brought back under control.

The set of practices, equipment and procedures used to keep formation fluids in the rock and prevent an influx from becoming a blowout.

The selection, inspection, attachment and use of slings, shackles and lifting points to raise or move a load safely.

Safe working load: the maximum load a sling, shackle or lifting point is rated to carry in a stated configuration, marked on the item and never exceeded.

A documented assessment of a lift that defines the load weight, centre of gravity, rigging arrangement, exclusion zone, personnel roles and contingency for the operation.

The practice of securing tools, inspecting lifting gear and using tethers, toe boards and exclusion zones so nothing falls from height onto people below.

Lifting, lowering, pushing, pulling or carrying a load by hand, planned to avoid injury through correct posture, team lifting and mechanical aids where possible.

The designated assembly area where personnel report and are counted during an emergency or drill, chosen to be upwind and clear of the hazard.

The documented set of alarms, roles, escape routes, shutdown actions and communication links that tells everyone on the rig what to do in a specific emergency.

The three elements needed for combustion - fuel, oxygen and heat - and the basis for extinguishing a fire by removing at least one of them.

A short pre-shift briefing in which the supervisor explains the task, the hazards, the controls and any changes, and the crew raise concerns before work begins.

The structured transfer of responsibility between crews or shifts, covering current operations, anomalies, open permits and outstanding maintenance so nothing is lost.

The daily record of footage drilled, mud properties, bit and string data, incidents, downtime and instructions that forms the legal and operational history of the well.