Portable Annulus Tester PAT™

Automated and cost effective riser annulus testing. The Portable Annulus Tester PAT™ is the latest development in 4Subsea’s strategy to digitise integrity management of flexible risers. The hand-carried unit allows for simple and cost effective annulus testing of risers using your own personnel.

Portable annulus tester

Typical Challenges for Operators


Do any of these apply to your subsea operations?

  • You don’t do annulus testing in a consistent and quality assured way across all your assets
  • You lack a consistent testing method independent of who performs the test
  • You want to reduce POB and utilise personnel familiar with your facilities
  • You need to get the test report immediately after the test
  • You need to decrease your costs of periodic annulus testing
  • You need 24/7 support during your testing


The fully automated and patent pending PAT™ unit has been developed based on 4Subsea’s worldwide experience with offshore inspection and testing of flexible risers. The objectives of such tests are to verify the flexible riser outer sheath integrity and the functionality of the ventilation system. The hand carried test unit performs complete annulus tests, and algorithms are enabling the operator to take immediate action if anomalies are detected. The system presents live results on the FlexTrack™ digital platform. 4Subsea performs certification programs for operators, training their personnel in using the Portable Annulus Tester.


PAT™ is an «Engineer-in-a-box» solution that removes the requirement for mobilising dedicated third-party personnel offshore. The system is the first in the world to completely automate and digitise riser annulus testing.


Take a look a a short demonstration video of the Portable Annulus Tester:


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Key Benefits

  • Operators avoid mobilising third-party personnel offshore
  • Enables a typical 30% cost reduction compared to traditional annulus test methods
  • Measures key asset integrity parameters and presents live results
  • Provides high degree of flexibility when planning test campaigns
  • Uses standardised algorithm of data interpretation to ensure consistent results and history of integrity assessments
  • Streamlines logistics with small, portable unit
  • Includes 24/7 4Subsea expert advice service


Key Features

  • Automated annulus free volume testing
  • Detects outer sheath breaches
  • Detects blocked vent ports
  • Detects liquid filling in annulus
  • Hardware and software fail-safe mechanisms
  • Touchscreen interface
  • Pre-programmed tests of site-specific risers
  • On-site test configuration/modification possibilities
  • Touch screen display with live test progress and results
  • Easy download of measured data to FlexTrack™
  • Portable, easy-to-use device