Vertical Subsea Tree Annulus and Controls Access

A wellhead assembly comprising:

• a tubular housing assembly having, an axial bore, and a housing annulus passage having a first end located at an outer diameter of the housing assembly and a second end located at surface of the axial bore, the housing assembly further having a housing tree interface surface, the housing tree interface surface being an annular upward facing sloped surface on an outer diameter of the housing assembly;
• a tubing hanger adapted to be secured to a string of tubing and selectively sealingly engaging the axial bore of housing assembly above the second end of the housing annulus passage, the tubing hanger having a vertical bore in fluid communication with the axial bore;
• and
• a vertical tree assembly selectively landed on the housing assembly, the vertical tree assembly having:
• a tree member located axially above the tubing hanger, the tree member having a lateral bore for directing a flow of production fluid from a well;
• a tree annulus passage with a first end at an upper interface of the tree member and a second end at an outer diameter of the tree member;
• an external annulus passage extending external of the tree member and the housing assembly, the external annulus passage in fluid communication with the housing annulus passage and the tree annulus passage;
• a valve assembly engaging the outer diameter of the tree member, the valve assembly having a tree open position to allow an annulus fluid to flow into and out of the tree annulus passage and having a housing open position to allow the annulus fluid to flow into and out of the housing annulus passage;
• and
• a tree wellhead interface surface, the tree wellhead interface surface being a downward and inward facing slope surface on an inner diameter of the vertical tree assembly that selectively engages the tree wellhead interface surface, supporting the vertical tree assembly on the housing assembly.

A method for completing a subsea well, the method comprising:

• (a) providing a tubular housing assembly having a housing sidewall, an axial bore, and a housing annulus passage extending from the axial bore through the housing sidewall and landing a blocking sleeve on the housing assembly so that the blocking sleeve circumscribes the housing assembly and blocks the housing annulus passage;
• (b) installing the housing assembly subsea at an upper end of the subsea well and performing drilling operations;
• (c) securing a string of tubing to a tubing hanger and landing the tubing hanger in the housing assembly, the tubing hanger having a vertical bore in fluid communication with the axial bore and then removing the blocking sleeve from the housing assembly;
• (d) providing a vertical tree assembly, the vertical tree assembly having a tree member, the tree member having a lateral bore for directing a flow of production fluid from the well and a tree annulus passage extending through a sidewall of the tree member, the vertical tree assembly further having an external annulus passage;
• and
• (e) landing the vertical tree assembly on the housing assembly so that the tree member is axially above the tubing hanger and so that the external annulus passage extends external of the tree member and external of the housing assembly and is in fluid communication with the housing annulus passage and the tree annulus passage.