Casing Head Assembly, are installed in the lower end of wellhead equipment, connected casing string and various wellhead equipment parts,which consist of body, casing hanger and seals. Casing head used for support intermediate casing and production string load, seal off annular space between the casings, provide fitter connection for installation of the BOP, tubing head and christmas tree. Surface casing are attached to the casing head bottom flange by means of flange, and production casing are attached to the casing head by means of thread.

Tubing Head Assembly, Tubing Head Assembly are installed on the upper end of the casing head, which consist of tubing head spool, tubing hanger and seals. Tubing hanger are used to support a tubing

string in a tubing head, sealoff the annual space between the tubing string and production casing. Tubing head spool are used to positive and reverse circulation well clean-up, observe casing pressure and carry out work through the annual space between the tubing string and casing string.

Christmas Tree Assembly, Christmas tree are installed on the upper end of the tubing head, which consist of gate valve, choke valve, tee/cross, flange and christmas tree cap, used to control and regulate the well

production, lead the oil or gas from the well into the pipeline, carry out the installation and remove of wellhead tools.