Enhanced Vertical Subsea Trees (EVXT)

FMC's guidelineless EVXT, is available in two models: a 5" x 2", 15,000 psi, 350º F (a High Pressure, High Temperature (HPHT) system) and a 4" x 2", 10,000 psi system

The EVXT tree is the world's most technologically advanced tree system and is rated for water depths of up to 10,000 feet. Numerous successfull systems have been successfully installed since 1998, making FMC the dominant subsea supplier of field proven subsea completion systems. The 10,000 psi EVXT system is currently operating on one of the world's deepest producing well, Shell Coulomb C-2, in 7,570 feet of water.

FMC EVXT Advantages:

Increased installation and operational flexibility over the horizontal tree
May be installed either before or after the well jumpers are connected between the flowline sled and the tree’s tubing head assembly
Provides substantial logistic benefits and related cost savings at an overall field development level
Tubing heads can be preinstalled in a low-cost manner (e.g. HCLS) from an anchor-handling vessel, if desired, prior to mobilizing a drilling rig for the subsea well completion activities.
Production tubing string can be installed before the trees are delivered. This is achieved by delivering the tubing head and tubing hanger assemblies on an accelerated schedule when this is beneficial to the client. Early delivery of tubing heads and tubing hangers allows wells to be completed in batch mode, which shortens rig time and allows the drilling rig to be released early
The trees can subsequently be installed using cable (or drill pipe, depending on vessel capability) from a variety of vessels, including anchor-handling vessels, construction vessels or drilling rigs, whatever best suites the operator’s cost targets and logistical needs with respect to vessel rates and availability. Due to this advantage, FMC’s customers have completed a ten tree installation program using these processes and averaged just one (1) single day of installation time on the drilling rig’s critical path for installation of the whole tree system, including the tubing head, tubing hanger, tree and tree cap.
EVXT's can be retrieved without de-completing the well if repairs are needed due to external damage.
FMC’s modern-design system is also as time-efficient as traditional horizontal trees during workovers that require the production tubing string to be retrieved. Tubing retrieval workovers are normally touted as a primary advantage for horizontal trees, but field experience with FMC’s Enhanced Vertical Tree system proves otherwise.
For workovers that only require access to enter the production tubing, vertical trees have an advantage over horizontal trees. Tubing access through vertical trees is achieved by simply opening valves in the tree and workover safety package. In comparison, two sets of wireline plugs need to be retrieved from the horizontal tree to gain access to the well bore. Wireline work is more time consuming and is potentially more troublesome than opening valves.

EVXT Features:

A dual bore tree, an ROV tree cap and a slim OD, concentric bore tubing hanger that is installed into a tubing head assembly. Using a tubing head provides numerous reliability and operational advantages, including a simplified wellhead interface, factory tested sealing surfaces for the tubing hanger, and a tubing hanger orientation system that is independent of the BOP.
The well jumper connects to the tubing head assembly instead of the tree to give the operator complete logistical flexibility over the sequence of tree and well jumper installations and retrievals.
A pressure-containing tree cap that is installed and retrieved by ROV off the rig critical path, saving days of expensive, deep water rig time.
The tree is designed to overcome flow assurance challenges in deep water by providing numerous chemical injection points and state-of-the art Novolastic™HT insulation, which is rated for 350º F.
The tree accommodates intelligent well completions with ease, featuring up to 11 downhole penetrations. All of this down-hole functionality is packaged into a slim OD tubing hanger system that will drift through slender 13-5/8" ID drilling risers to provide life-of-field intervention advantages.
A workover riser system is field proven aboard one of the largest and most sophisticated dynamically positioned drill ships in the world. It provides quick disconnect, fail-safe functionality and is reliaby operated by an electro-hydraulic control system with acoustic back-up.
High-Pressure, High-Temperature (HPHT) subsea completion system up to 10,000 ft. water depth rating and 17D temperature class: 0° - 350°F
Capable of providing up to 11 downhole lines for control, monitoring and chemical injection
Annulus flowloop is integral to the composite valve block and the production wing block
Premium FMC Model 3000 metal sealing gate valves are used for production, annulus, and crossover valves
2" and 5" 15K actuated valves use M3000 actuators with linear override
Premium FMC M175 metal sealing actuated gate valves are used to isolate chemical injection lines
Metal sealing needle valves are used to isolate test lines
Material class: "HH" with inlaid ring grooves and sealing areas, NACE, H2S service
Tree, tubing head and tubing hanger designed in accordance with API 17D PSL-3