This section will compare the pros and cons of both vertical subsea trees and horizontal subsea trees and list the criteria to select a subsea tree.
A subsea horizontal tree is designed so that all flow control valves are outside the central wellbore. A tubing hanger is located inside of a subsea horizontal tree body. A horizontal tree is well known as a workover friendly tree because it offers easy access for tubing retrieval because the valves are not located at the centre of the wellbore. Figure 1 shows an image of a horizontal subsea tree from GE oil and gas.
Figure 1 – Horizontal Subsea Tree Model VetcoGray M-Series MVXT and MHXT (Courtesy of GE Oil & Gas)
