L4 - X’MAS TREES • X’MAS TREES - DUAL BORE TREES - HORIZONTAL (SPOOL) TREES - VALVES & ACTUATORS - DEEPWATER TREES - ALL ELECTRIC TREE - DRILL THRU SPOOL TREE
18 ¾” HP wellhead housing
Wellhead to casing hanger Metal Seal assembly Bypass Area Wellhead to casing hanger Metal Seal assembly Passive Pre-loaded lockdown system
7” casing hanger – For Glenelg the tubing hanger is at this elevation and replaces the 7” casing hanger 10 3/4” casing hanger 13 3/8” casing hanger Wellhead to casing hanger Metal Seal assembly High strength load shoulder
H-4 Vetco Profile 10 3/4” casing 13 3/8” casing 20” casing 30” conductor A Annulus B Annulus C Annulus
TYPICAL SUBSEA WELLHEAD Cameron Profile
SUBSEA X’MAS TREE FUNCTIONS •
Basically a stack of valves installed on a subsea wellhead to provide a controllable interface between the well and the production facilities.
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Specific functions of a subsea Christmas tree : – Sealing the wellhead from the environment by means of the tree connector – Sealing the production bore and annulus from the environment – Providing a controlled flow path from the production tubing, through the tree to the production flow line. Well flow control by means of tree valves and/or a tree-mounted choke valve. – Providing access to the well bore via tree caps and/or swab valves. – Providing access to the annulus for well control, pressure monitoring, gas lift, etc. – Providing a hydraulic interface for the down hole safety valve. – Providing an electrical interface for down hole instrumentation, electric submersible pumps etc. – Providing structural support for flow line and control umbilical interface.
Horizontal / Spool Tree
Conventional Dual Bore Tree
VALVES PRODUCTION • Master Control Valve • Wing Valve • Swab Valve or Plug VALVES – ANNULUS • Control * Wing Valve • Swab Valve
2” Tubing
5 1/2 Tubing
TREE VALVES
CROSSOVER VALVE
5 1/2, 7” or 9 5/8 Tubing
FAIL SAFE HYDRAULIC ACTUATOR Gate Valve Slide
Bore with Gate in open position Valve stem moved by hydraulic fluid
Actuator Spring compressed If hydraulic pressure is lost to the actuator (by design, activated by the control system OR if in an emergency the umbilical is cut) then the spring returns the valve to a safe closed position
Dual Bore X’Tree • Designed to allow vertical access to the main production bore and to the annulus bore during installation and workover operations. • When a dual bore subsea Christmas tree is connected to a subsea wellhead it must interface with the tubing hanger previously installed in the wellhead. The tubing hanger and tree must be correctly orientated so that the production and annulus bores are properly aligned and sealed. • Accomplished by interaction of a pin and helix between the tubing hanger running tool and the BOP
DUAL BORE TREE SUBSEA X’MAS TREE MANUFACTURERS •
COOPER CAMERON
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FMC KONGSBERG
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VETCO GREY
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KVAERNER NATIONAL
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DRILQUIP
X’MAS TREE SCHEMATIC WITH CONTROL SYSTEM
Note all control functions pass through the Tree Cap. With Tree Cap removed the control functions can be taken over by a drilling rig.
DUAL BORE X’MAS TREES
OSENBERG Tree
DRIL QUIP Showing Protection frame
Horizontal X’Trees •
“Side valve tree” or SpoolTree™.
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Most obvious distinction from the dual bore tree: the production and annulus bores branch horizontally out of the side of the tree body /valves on a horizontal axis.
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No production or annulus swab valves. Access to the well bore by removing the internal tree cap, or a wireline plug within the internal tree cap.
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Other distinguishing features of the horizontal tree: 1. 2.
the tubing hanger is installed in the tree itself, rather than in the wellhead and the top of the tree is designed so the BOP may be landed onto the tree. This arrangement allows the tubing string to be recovered without first retrieving the tree.
HORIZONTAL TREE 5.5” TUBING WITH 4” PRODUCTION CHOKE & 2” GAS LIFT CHOKE
