How does a christmas tree valve system work in oil drilling ?

explain the mechanism behind the structure as wellHow does a christmas tree valve system work in oil drilling ?
The site below has a pretty good picture and description of a christmas tree with the valves.





Most oil wells have two pipes that extend to the area where the oil and gas are located. One is the outer pipe called the production casing. It seals the well bore from all the outside dirt, rock and other stuff that the well is drilled through.





Inside the casing is usually a smaller pipe called the production tubing. This is the pipe that the oil and gas runs through to get from the bottom of the well to the surface.





There are several variations on this basic concept but that isn't important to your question. There is a more complete discussion of oil wells at the second site below.





The christmas tree is a valve assemble that is designed to fit on the casing and attach to the tubing so the well and be controlled, maintained and worked on.How does a christmas tree valve system work in oil drilling ?
It controls the oil and gas flow out of the oil well.





It sits on top of the well, and is placed there before breaching the reservoir. You can drill through new types of horizontal XT (christmastrees) and do down-hole operations without removing the main valve and tubing hanger.





Basically it is a safety and flow-controlling valve that you can turn on and off (and adjust) the oil and gas flow of a well.





Hope that answers your question :)
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