A Christmas Tree is an assembly of valves, spools, and fittings used to regulate the flow of pipes in a well that is connected to the top of a well to direct and control the flow from the well. The Christmas Tree and Wellhead are used interchangeably; however, a wellhead and Christmas Tree are entirely separate pieces of equipment. A wellhead must be present in order to utilise a Christmas tree and can be used without a Christmas Tree during drilling operations.

Reference Definition by Oilfield.slb.com: A Christmas Tree is an assembly of valves, spools, pressure gauges and chokes fitted to the wellhead of a completed well to control production. Christmas trees are available in a wide range of sizes and configurations, such as low- or high-pressure capacity and single- or multiple-completion capacity.

Related Definitions in the Project: The Upstream Engineering