a complete oil or gas production system consists of a reservoir, well, flowline, separators, pumps, and transportation pipelines. The reservoir supplies wellbore with crude oil or gas. The well provides a path for the production fluid to flow from bottom hole to surface and offers a means to control the fluid production rate. The flowline leads the produced fluid to separators. The separators remove gas and water from the crude oil. Pumps and compressors are used to transport oil and gas through pipelines to sales points.

The reservoir is the source of fluids for the production system. It is the porous, permeable media in which the reservoir fluids are stored and through which the fluids will flow to the wellbore. It also furnishes the primary energy for the production system. The wellbore serves as the conduit for access to the reservoir from the surface. It is composed of the drilled wellbore, which normally has been cemented and cased. The cased wellbore houses the tubing and associated subsurface production equipment, such as packers. The tubing serves as the primary conduit for fluid flow from the reservoir to the surface, although fluids also may be transported through the tubing-casing annulus.

The wellhead, flowlines, and processing equipment represent the surface mechanical equipment required to control and process reservoir fluids at the surface and prepare them for transfer to a purchaser. Surface mechanical equipment includes the wellhead equipment and associated:

  • Valving
  • Chokes
  • Manifolds
  • Flowlines
  • Separators
  • Treatment equipment
  • Metering devices


The Total Components in the Production System Can be Classified as Follows


a) Well Head

  1.  Casing head
  2. Casing spool
  3. Casing Hanger
  4. Tubing Head
  5. Tubing Hanger
  6. Tubing Head Adaptor

b) Christmas Tree

  1.  Production Wing Valve
  2.  Master Valve
  3.  Kill Wing Valve
  4. Swab Valve
  5. Tree cap
  6. Crossflow cap

c) Chokes


a) Casings

b) Tubing

c) Landing nipple

d) Circulating devices

e) Blast joint

f) Flow coupling

g) Expansion joint

h) Pup Joint

i) Tubing Safety Joint

j) Packer

k) Subsurface safety valves