How to hang the tubing in the wellhead?
　　Wellhead equipment shall have a set of equipment that can control and regulate oil and gas production. Wellhead equipment is called wellhead equipment, usually called Christmas tree. The wellhead equipment has the following main functions:
　　(1) The weight of all tubing strings supporting the well is suspended in the tubing;
　　(2) Sealing annular space between tubing and casing;
　　(3) Adjustment of wellhead equipment and well production;
　　(4) Ensure all kinds of underground operation, such as overhaul and minor repair;
　　(5) It can carry out daily production management, such as obtaining oil pressure, casing pressure data, pressure measurement and paraffin removal.
　　

There are three types of wellhead devices
　　1. Wellhead equipment, casing brake, main brake, production brake, wax brake, tubing fork and oil nozzle.
　　2. The pumping wellhead is simpler than the flowing wellhead. The basic part is composed of casing tee, tubing tee and polished rod seal box.
　　3. The blowout tree is a kind of gas wellhead device with the same structure as the blowout wellhead device. Due to the high pressure of natural gas well and the presence of hydrogen sulfide gas, the wellhead equipment should have a high pressure level and be able to resist the corrosion of hydrogen sulfide gas.