Wellhead assembly and Christmas treeWellhead assembly and Christmas tree, important equipments for oil and gas production, consist of three parts: casing head, tubing head and Christmas tree, which are mainly used to connect casing string and tubing string, seal annular space between casing pipes and tubing pipes of each layer, control the pressure of producing wellhead and adjust the flow of oil or gas wells, also available to acid fracturing, water injection, tests and other special operations.
