... control the production quality.Wellhead Equipment & Christmas TreeX'mas tree is a key equipment to control the pressure in ... the flowrate of oil/gas well in oil/gas production. 1. Fix drilling wellhead, connect wellhead casing string, seal ... 2. Consist of casing head, tubing head and Christmas tree 3. Apply to all kinds of casing, tubing programs ... BB, CC, DD, EE, FF Well Head Equipment & Christmas Tree