A Christmas Tree is a critical equipment of the completion string and production equipment. It is also referred as X-Mas Tree because its shape resembles to a Christmas tree during Christmas festival. It has a set of valves including a master valve and wing valve, a choke and connections and is installed on top of the tubing head spool of the wellhead.

Purpose of the Christmas tree is as follows:

•          It provides a means to control the flow of production fluids from the well which serves as the primary purpose of this equipment.
   
•          It diverts the fluid flow through the wing valve to the flow lines ensuring safety of the facilities.
   
•          Provides a means for measurement tools and instruments an access to the well.
   
•          Provides a means to inject chemicals or oil distillates to prevent or solve production problems such as blockages.
   
•          Helps in controlling the gas or water injection into the well in order to maintain an economic production volumes.
   
•          Tree acts as an attachment and conduit means of the control system to the downhole safety valve.

Christmas tree includes the following components:

•          Tree cap and gauge
   
•          Tree adapter
   
•          Swab valve
   
•          Kill wing valve
   
•          Production wing valve
   
•          Surface choke
   
•          Master Valves (Upper and Lower master valves)
   
•          Tubing head adapter
   
•          Production string

 

The Christmas tree is operated either from a control room i.e. it is hydraulically actuated or it can be manually operated by rotating the handwheel of the valves attached to it.