Main Components of Subsea Tree

Components of subsea Xmas tree vary according toe the specific design requirements of specific subsea fields. 

Typical vertical tree components are as below:

• Tree cap
• Upper production master valve (UPMV)
• Lower production master valve (LPMV)
• Production wing valve (PWV)
• Production swab valve (PSV)
• Crossover valve (XOV)
• Annulus master valve (AMV)
• Annulus access valve (AAV) or annulus swab valve (ASV)
• Annulus wing valve (AWV)
• Pressure and temperature sensors (PT, TT, PTT, etc.)
• Tree connector
• Conventional tubing hanger system

Typical components of horizontal tree are as below:

• Tree debris cap
• Tree body
• Internal tree cap (or upper crown plug)
• Crown plug (or lower crown plug)
• Production master valve (PMV)
• Production wing valve (PWV)
• Production swab valve (PSV)
• Crossover valve (XOV)
• Annulus master valve (AMV)
• Annulus access valve (AAV) or annulus swab valve (ASV)
• Annulus wing valve (AWV)
• Pressure and temperature sensors (PT, TT, PTT, etc.)
• Tree connector
• Tubing hanger system

The main components that vary between vertical tree and horizontal tree are as follows:

• Tree body: The tree body in a horizontal tree is normally designed to be an integrated spool. The PMV is located in this tree body, as well as the annulus valves. The PWV is usually designed to be integrated into a production wing block, which can be easily connected to the tree body by flange methods. This design results in components that are interchangeable between the horizontal xmas tree in the industry. In addition, the tubing hanger system is located in the tree body.
• Tubing hanger system: Vertical xmas tree utilizes a conventional tubing hanger, which has a main production bore and an annulus bore. The tubing hanger is located in the wellhead. However, in horizontal xmas tree, the tubing hanger is a monobore tubing hanger with a side outlet through which the production flow will pass into the PWV. Because the tubing hanger in horizontal xmas tree is located in the tree body, it needs the crown plugs as the barrier method. An internal tree cap is the second barrier located above the crown plug. If dual crown plugs are designed in a tubing hanger system, an internal tree cap is not used.
• Tree cap: The tree cap in a vertical xmas tree system has the functions of providing the control interfaces during workover and sealing the tree from seawater ingress. An horizontal xmas tree, in contrast, has internal tree caps and tree debris caps.