Introducing WATTS, an Astrimar development to reduce costs

Executive Summary

WATTS is Astrimar’s bespoke solution to integrate deflector base functionality into a simplified system for use with a CAN-ductor product, resulting in reduced cost and increased installation efficiency – an industry first solution.

Challenge

Our client engaged us to first develop a concept, followed by detailed design and manufacture of an alternative, more cost-effective solution to a conventional OEM deflector base while maintaining or enhancing the same wellhead alignment and fishing gear torque transfer capabilities.

Solution

Astrimar developed a highly innovative, initial concept in the form of a Wellhead Alignment and Torque Transfer System (WATTS), to effectively replace a conventional deflector base. By uniquely decoupling its required functions, we designed independent solutions to address each function. This resulted in a system that provides improved tolerance stack up and alignment, effective torque transfer, reduces manufacture costs and simplifies installation. Astrimar’s scope included conceptual and detailed engineering, engineering analysis, technical risk assurance, including FMECA, manufacture management and test program development.

Results

Having accepted our concept, our client contracted Astrimar for the detailed engineering design and analysis, manufacture, testing and subsea installation, initially on two new subsea wells. Additional systems have since been manufactured for deployment.

WATTS Functional Design Details:

• WATTS provides effective interfacing with the outside of the Low Pressure Housing LPH, locking into the cement ports
• Is fully assembled onshore and deployed together with the CAN-ductor in a single operation
• Provides effective positioning and alignment of guideposts relative to the wellhead
• Provides snag-load torque-transmission functionality from XT/Flowbase into the CAN-ductor
• Transmits line-load and torque directly into the CAN, while the existing Deflector Base design transmits torque and line load to the LPH
• WATTS Trawl-board and line-load snag resistance in line with NORSOK-U101
• Incorporates a trawler friendly design to reduce risk of snagging
• Provides ROV operable guidepost locking functionality
• Provides ROV docking functionality through integrated ISO13628-8 TDU interface
• Incorporates ROV grab-handles for functioning guidepost locking-pins and torque reaction pins
• Incorporates cement return lines from the LPH to the outside of the CAN-ductor envelope. Four hoses of 4” diameter
• Has minimal stiffening effect on the wellhead – hence no effect on wellhead fatigue life
• Design life of 20 years (based on provided cathodic protection)

Benefits of WATTS:

WATTS provides numerous advantages over a conventional deflector base:

• Simplified design resulting in significantly reduced manufacturing costs compared to a conventional Deflector Base
  • Significantly reduced and simplified tolerance stack-up between the wellhead and guideposts, resulting in improved alignment accuracy
  • Snag loads are transmitted directly into the CAN-ductor due to the decoupled design of WATTS, bypassing the wellhead, resulting in improved system integrity and reliability
  • Modular design, enabling parallel manufacturer and simplified onshore installation
  • Minimal effect on overall system stiffness with not change to the fatigue life of the wellhead system, due to the decoupled nature of the design

For more information, visit: www.astrimar.com

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