Portable Annulus Tester PAT™

Automated and cost effective riser annulus testing. The Portable Annulus Tester PAT™ is an “Engineer-in-a-box” solution that removes the requirement for mobilising dedicated third-party personnel offshore. The patent pending system is the first in the world to completely automate and digitise flexible riser annulus testing. 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


Most oil companies operating flexible risers carry out annulus testing on an annual basis to ensure the integrity of the risers, and to detect anomalies early. The objectives of such tests are to verify the flexible riser outer sheath integrity and the functionality of the ventilation system. With the patent pending Portable Annulus Tester PAT™ we have eliminated the need to send two technicians or engineers offshore by helicopter to perform the tests.

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 results on the FlexTrack™ digital service, accessible to both onshore and offshore personnel. 4Subsea performs certification programs for operators, training their personnel in using the Portable Annulus Tester. PAT™ is the latest development in 4Subsea’s strategy to digitise integrity management of flexible risers.

Riser replacement or production shutdown due to riser failure entail significant costs, and frequent testing of flexibles reduces the chance of riser failure. Unplanned riser replacements and production downtime can be avoided. With PAT™ testing is automated and results are digitised and available immediately during testing.


PAT™ is an «Engineer-in-a-box» solution that removes the requirement for mobilising dedicated third-party personnel offshore. The solution typically reduces annulus test cost by 30% in the North Sea, while in remote regions simplified logistics reduces cost far beyond the 30% experienced in Northern waters.


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


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Key Benefits

  • Operators avoid mobilising third-party personnel offshore
  • Enables significant cost reduction compared to traditional annulus test methods
  • Measures key asset integrity parameters
  • Results are digitised and presented immediately during testing
  • 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

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