Christmas Tree & Tubing Heads
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.
The main bearing pieces of the Christmas tree and the tubing heads are forged or cast, with the advantages of high bearing capacity, safety, reliability, etc.
Tubing Head Cross-Tee
1. Structure of Tubing Head
Usually, the tubing head is the cross-tee connected by flange both at top and bottom. The tubing head is installed on the flange of the casing head, so as to hang the tubing string and seal the annular space between the tubing string and the production casing. The tubing head is made up of the tubing head cross-tee and the tubing hanger.
2. Functions of Tubing Head
1) to hang the tubing string;
2) to seal the annular space between the tubing and the sleeve;
3) to assist to connect the casing head and the Christmas tree;
4) The 2 side ports on the tubing head cross-tee could be used for water adding and washing well.
3. Tubing Hanger
The tubing hanger is used to support the tubing string and seal the annular space. The tubing hanger is sealed so that it’s convenient for operation. It’s with the advantages of the rapid speed and safe performance. Thus, it’s widely used for the middle or deep wells and the normal wells.
The tubing head cross-tee could completely satisfy the requirements of API 6A. It’ s with the advantages of high bearing capacity, safety and reliability. There are two kinds of side outlets, including the thread one and the cutting-silk one. The cutting-silk side outlet is with 1（1/2）LP inner thread.