Guidance on subsea metrology
- Informative Guidance
- Revision 2 - October 2025
This document provides comprehensive guidance on the planning, execution, and reporting of subsea spoolpiece metrology, with information on nine key metrology methodologies used to obtain dimensional data for the design and installation of subsea pipeline connections.
It covers the key principles, equipment and methodology, including:
- long baseline acoustics
- diver taut wire
- digital taut wire
- photogrammetry
- INS
- acoustically aided INS SLAM
- sonar
- static subsea LiDAR, and
- dynamic laser scanning.
The document is intended as informative guidance for surveyors, engineers, and contractors, helping them select appropriate metrology methods and understand their impact on fabrication tolerances and operational safety.
Contents
- Glossary
- Introduction and Overview
- Subsea Metrology Planning and Preparation
- Subsea Spoolpiece Metrology Survey Methods
- Subsea Metrology Deliverables
- Further Reading
- Appendix A – Typical Examples of Metrology Brackets
- Appendix B – Typical Examples of Laser Scanning Targets
- Appendix C – Comparison of Subsea Metrology Systems
- Appendix D – Summary of Equipment Requirements for Metrology
- Appendix E – Statistical Confidence in Accuracy Reporting
Revision
-
Rev. 2 - October 2025Title revised to include the word spoolpiece. Updates to each section to align with current technology and methodology. Appendices expanded to include an equipment summary and information on using statistical confidence in the reporting of accuracy.
-
Rev. 1.1 - February 2024Update of page 2 and reference links; bookmarking (layout) improved; no change to content
-
Rev. 1 - September 2017To include updated material
-
Rev. - February 2012Initial publication