|The space between the drill pipe and hole wall or casing inside surface.
|Bottom Hole Assembly.
|The steel plate that locates the bit in the rotary table while it is screwed onto/made up to the drillstring.
|Blow Out Preventer, a series of valves that close to seal in the well and prevent it blowing out.
|Formation that has fallen out of the well bore wall down hole.
|Heavy drill pipe used in the BHA to add weight.
|Attempting to recover an item out of the well bore to surface.
|Gallons Per Minute.
|Health, Safety and Environment.
|Hydraulic horsepower per Square Inch.
|The heavy steel drive shaft with a square or hexagonal cross section that locks in the rotary table and is connected to the drillstring to transmit torque.
|Lost Circulation Material.
|Logging While Drilling.
|Measurement While Drilling.
|Oil Based Mud.
|Root Mean Square (a method of averaging a signal).
|Rate of Penetration, fph/mph.
|Device on the rig floor used to drive/rotate the kelly and support the drillstring.
|Combination Revolutions Per Minute.
|Rock Strength Analysis.
|Polycrystalline Diamond Compact.
|Pseudo Oil Based Mud.
|Personal Protective Equipment.
|Pounds per Square Inch, fluid pressure.
|While directionally drilling with a motor, the rotary drive is switched off so the drillstring does not rotate and is ‘slid’ downhole
|Strokes Per Minute.
|Stand Pipe Pressure.
|Burying the bit face into material, eg: the hole bottom or casing shoe assemblies.
|Total Flow Area, the sum of the cross-sectional areas of the exits of all nozzles in the bit.
|The direction the motor is orientated to in hole while sliding.
|A torsional motor used to drive the drill string. Usually installed on the bigger rigs and can provide more power than a kelly drive.
|Water Based Mud.
|Weight on Bit, klbs/tonnes.