General Terms

Well Types

  • Exploration – Wild Cat
  • Delineation
  • Appraisal
  • Development
  • Injectors

Well Designs

  • Conventional Design – Telescopic
  • Complex Design – Manobore
  • Hole Sections
  • Different phases
  • Surface Hole
  • Intermediate holes
  • Production hole drilling phase
  • Riser
  • Drive Pipe
  • Conductor Casing
  • Surface Casing
  • Intermediate Casings
  • Protective Casings
  • Production Casing
  • Tubing
  • Liners and Tiebacks

Designs of Wells

  • Vertical/Near Vertical
  • Directional Wells
  • Horizontal Wells
  • Extended Reach Wells
  • Multilateral Wells

Main Components of a Drilling Rig

  • Hoisting Component
  • Rotating
  • Circulating Component
  • Power and Prime Movers
  • Well Control Component

Well Control Equipments

  • Wellhead
  • Casing Spool
  • Drilling Spool
  • Spacer Spool
  • Blowout Preventers (BOP)
  • Valves
  • Accumulators
  • Choke and Kill Lines
  • Choke and Kill Manifolds

Drillstring Sections

  • Different Components:
  • Kelly
  • Upper and Lower Kelly Cocks
  • Drill Pipe (DP)
  • Heavy Weight or Heavy Wall Drill Pipe (HWDP)
  • Drill Collar
  • Subs
  • Downhole Drilling Tools
  • Reamers
  • Stabilizers
  • Downhole Motor
  • Drilling Jar
  • Accelerators
  • Measurement While Drilling Tools (MWD)
  • Logging While Drilling Tools (LWD)
  • Pressure While Drilling Tools (PWD)
  • Seismic While Drilling Tools. (SWD)


  • Types of Bits
  • Roller Cone
  • Fixed Cutter Bit

Formation Pressures

  • Abnormal pressure > 0.465 psi/ft
  • Normal pressure = 0.465 psi/ft
  • Sub-normal pressure < 0.465 psi/ft

Completions Types

  • Open-hole completions
  • Cased hole completion
  • Monobore Completions
  • Multi-Lateral Completions
  • Intelligent Completions
  • Artificial Lift systems


  • Annulus:
    The space between hole (wellbore, casing) and the outside the pipe (drillpipe, casing, tubing etc). Drilling fluid is pumped through the drillpipe and then up the annulus.
  • TOC
    Top of the cement in the annulus.
  • TOL:
    Top of liner.
  • Casing Seat:
    It is the setting depth of the casing or end of the casing where it is cemented in a particular phase. It is also referred as casing shoe depth.
  • BHA:
    Abbreviation for Bottom Hole Assembly. The part of the drill string from bottom of the DP (which is top of the DC) to the bit. Generally includes bit; subs, stabilizers, reamers, other downhole tools and all drill collars. Can also include Heavy Weight drillpipe.
  • Formation:
    Various kinds of rock with different or same mineralogy that the well will be drilling.
  • MD and TVD
    Measured depth along the well and TVD is the true vertical depth of the well.


Drill pipe (DP), Heavy weight drillpipe (HWDP), drill collar (DC), casing (csg) and tubing (tbg) described the following data:

  • Outside diameter (OD)
  • Weight of pipe (pounds/f t, #/ft, ppf)
  • Grade of the pipe (Combination of letter and number for example: grade K-55). The number represents the yield of the pipe multiplied by 1000 psi)
  • Length of the pipe (ft, m)