Typical Subsea XT systems require a connection to be made between the XT or Tubing Head (THD) and the Subsea wellhead system.  Such a connection requires the integrity to handle high loading that can be induced by the drilling, intervention and workover operations.  This is particularly true of HPHT equipment where heavier BOPs and larger rigs are required to deal with this challenging environment.  As such, new products and techniques are required that can provide the required static and cyclic capacities required in such operating conditions while still being cost-competitive in the current Oil and Gas environment.

To meet this challenge we have developed a new family of wellhead connectors that, through their innovative design, provide the required levels of static and cyclic capacity while delivering significant cost savings over traditional wellhead connector products. 

Such wellhead connectors are a critical product in the Subsea system due to their position at the base of the completion and workover riser system.  As such they are subject to verification and validation requirements from a variety of industry standards such as API 17D, Norsok U-001, API 17TR7 and API 17G.  API 17 TR8  also provides specific guidance on methods allowed when designing equipment for HPHT uses.  Over these industry standards a range of analysis techniques are allowed based on a variety of analysis codes each of which uses different factors to determine a design margin from failure to a safe working load.  Currently, only the 2nd Edition of API 17G requires a test to failure in order to validate the actual design margins the different codes allow to be defined.  Some recent work presented at the Offshore Technology Conference (OTC-27605) has shown the actual design margin how some of these techniques in simple test specimens.  Overall though, there is a lack of published evidence of how these methods can effectively determine the design margins of complex, highly loaded components. 

In order to meet the requirements of the industry and to ensure product integrity we have developed and implemented a HPHT verification and validation methodology based on API 17TR8 / ASME SEC VIII Division 3 method for use on our wellhead connector designs.  This paper shall present the results of a series of verification and full scale validation tests to failure to prove the design margins of a wellhead connector family.  In addition to definition of design margins analysis will be made with the FEA predicated capacities compared to actual capacities, impact of actual material properties versus minimum specified and comparison of strain gauge data.  


Asme Sec Viii Div. 3 and Api Tr 17tr8 Verification and Validation Methodology for Subsea Connectors

Division / Sponsors: 
Pressure Vessels & Piping (PVP)


Paper Proceedings: https://asmedigitalcollection.asme.org/PVP/PVP2020/volume/83815

PVP2020 - Virtual Conference

Supporting the need among researchers worldwide for additional online and multimedia content, ASME now offers the ASME Conference Video Collection. This platform will collect and provide long-term access to conference presentation videos, encompassing all technology areas within ASME's technical conference and events program. About 30,000-40,000 engineers across all mechanical engineering and related disciplines participate in ASME conferences each year. This includes authors of approximately 6,000 to 8,000 technical papers published by ASME, the majority of whom also submit video presentations for our virtual conferences. The video collection will be available as an add-on to existing product packages or as a separate subscription.