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.