Xmas Trees
Primary flow control system for
well once in production
Features and access requirements
•Outflow from well - production
•Inflow to well - injection or killing
•Vertical access to tubing - wire line, coiled tubing
Xmas Tree Components
•Pressure gauges
(accessory)
– safety
hazard / potential wrong pressure readings
•Gauge flange or tree cap
–provides seal
for top of tree
•Lubricator valve
–isolate
pressure, well access for intervention tools
•Flow tee
–used to direct
flow, enable thru-tubing access
•Production wing valve
–used to isolate
well for most routine operations
•Kill wing valve
–enables
connection of pumping equipment
•Choke
(accessory)
–controls rate of
flow from well
•Master valves (main isolation
valves)
–Upper Master
Valve (operational valve), optional: hydraulic / pneumatic
controlled
Surface Safety Valve
Surface Safety Valve
–Lower Master
Valve (back-up valve)
manually operated
Categories of Xmas Tree
Flanged tree
•Several flanged components
–
each connection is a potential leak path
•Much more common than monoblock design
•More flexible than monoblock design
•takes up more space (height)
Monoblock construction tree
•Single block construction
•Fewer possible leak paths
•Used in high pressure/leak sensitive locations
Monoblock Xmas Tree
Comprises inline or "Y"
shaped block of single casting/forging
Valving arrangement
•Lower Master Valve (manual)
•Upper Master Valve (Surface Safety Valve)
•Y piece or side outlet flanges
–houses both
production and kill wing valves
•Uppermost valve (manual swab valve)
Multiple Completions
Cases where more than one
completion string installed
•Each
string independently
suspended
•Must
seal off tubing casing annulus
–either independently or
collectively
•Independent
control of fluid flow in each string
Xmas Tree Selection
produce a listing of the
parameters of the anticipated process or operating envelope
- Classify the Well Type
Water Well ( low or medium pressure, Rate )
Oil Well (low, medium or high pressure, GOR, Rate )
Gas Well ( low, medium or high pressure, WGR, Rate)
This will be the basis for
the design and the selection of equipment type and rating
wellhead installation
