... :-46-121 4)material class:AA-HHIn petroleum and natural gas extraction, a Christmas tree is an assembly of valves, spools, and ... fittings used for an oil well, gas well, water injection well, water disposal well, gas injection well, condensate well and other ... .9.The Christmas tree could be used for oil exploration, gas exploration, water adding, compression fracture, acidification, etc.10.The ...