The Christmas tree is the assembly of the valve and the accessories, which is used for the fluid control of the oil/gas well, and supplying the inlet for the tubing string. The Christmas tree refers to all the devices on the tubing head and the flange. The Christmas tree could be assembled differently so as to meet the different requirements. The Christmas tree could be used for oil exploration, gas exploration, water adding, compression fracture, acidification, etc. The different Christmas trees are with the different pressure grades.
The Christmas tree and the tubing heads are mainly used for gas exploration and adding. Because the natural gas is with the low relative density and adding pressure, while the wellhead is with the high pressure and flow rate, it would be easy to leak. Sometimes, there’s H2S, CO2 and other corrosive medium in the natural gas. It would have the more strict requirements on the sealing capacity and the sealing materials of the Christmas tree. Thus, the tube and the sleeve should be with double valves. The valves should be forged by the best-quality steel for the high-pressure or extra-high-pressure gas well.
