Comparison of Vertical-Bore and Horizontal Subsea Production Trees
Subsea tree

The subsea production tree is an arrangement of valves, pipes, fittings, and connections placed on top of a wellbore. Orientation of the valves can be in the vertical bore or the horizontal outlet of the tree. The valves can be operated by electrical or hydraulic signals or manually by a diver or ROV.

The function of is to provide control of the well's flow and to monitor well conditions at the tree and the well's subsurface conditions. There are two types of subsea trees, vertical and horizontal.

Vertical trees

Vertical trees are configured similar to traditional surface trees with inlet valves. This configuration restricts access to the well bore due to the internals of the valve. Vertical subsea trees usually have essentially the same basic components of a typical dry tree, including shut-down valves, annular pressure ports, pressure and temperature ports, etc.

Horizontal trees

Horizontal trees have similar components of a typical dry tree, but they are configured to allow access to the well without having to pass through internal valve components. Large diameter tools can be used on horizontal trees since they do not have to pass through the valves on the tree.

Daisy chain trees

The daisy chain tree has direct connection with an isolation valve into the built in segment of flowline. An incoming and outgoing flowline will connect to the daisy chain tree. The daisy chain configuration allows any tree or number of trees to be shut-in and isolated from the flowline, thus allowing production to continue from the unaffected wells.


  • C. Haver, Industry and Government Model for Ultra-Deepwater Technology Development, OTC 2008, Topical Luncheon Speech, Houston, 2008.
  • C.W. Burleson, Deep Challenge: The True Epic Story or Our Quest for Energy Beneath the Sea, Gulf Publishing Company, Houston, Texas, 1999.
  • M. Golan, S. Sangesland, Subsea Production Technology, vol. 1, NTNU (The Norwegian University of Science and Technology), 1992.
  • Minerals Management Service, Deepwater Gulf of Mexico 2006: America’s Expanding Frontier, OCS Report, MMS 2006-022, 2006.
  • J. Westwood, Deepwater Markets and Game-Changer Technologies, presented at U.S. Department of Transportation 2003, Conference, 2003.
  • FMC Corporation, Subsea System,, 2010.
  • H.J. Bjerke, Subsea Challenges in Ice-Infested Waters, USA-Norway Arctic Petroleum Technology Workshop, 2009.
  • International Standards Organization, Petroleum and Natural Gas Industries-Design and Operation of the Subsea Production Systems, Part 1: General Requirements and Recommendations, ISO, 2005, 13628-1.
  • International Standards Organization, Petroleum and Natural Gas Industries-Design and Operation of the Subsea Production Systems, Part 6: Subsea Production Control Systems, ISO, 2000, 13628-6.
  • M. Faulk, FMC ManTIS (Manifolds & Tie-in Systems), SUT Subsea Awareness Course, Houston, 2008.
  • C. Horn, Flowline Tie-in Presentation, SUT Subsea Seminar, 2008.
  • S. Fenton, Subsea Production System Overview, Vetco Gray, Clarion Technical Conferences, Houston, 2008.
  • P. Collins, Subsea Production Control and Umbilicals, SUT, Subsea Awareness Course, Houston, 2008.