Article Article
Comprehensive Site Integrity Assessments and Mitigations for Unbonded Flexible Pipes

Unbonded flexible pipes have become a new trend in the oil and gas sector for transporting hydro-carbon products due to good service, reliability, and ease of installation, which can be translated to cheaper cost during design, manufacturing, instal-lation, and operations. However, due to limited inspection options during operation, unbonded flexible pipes are exposed to a greater risk of failure compared with conventional steel pipes. This paper investigates a new inspection approach to perform complete site integrity assessments of unbonded flexible pipes, which can be divided into three sub-activities: ultrasonic testing (UT), visual testing (VT), and cathodic protection survey. These activities will be conducted consecutively prior to performing any repairs. This paper also discusses mitigations and repair measures when there is damage to the unbonded flexible pipe.


API, API Recommended Practice 17B: Recommended Practice for Flexible Pipe, 3rd ed., The American Petroleum Institute, Washington, D.C., 2002.

API, API Standard 17J: Specification for Unbonded Flexible Pipe, 4th ed., The American Petroleum Institute, Washington, D.C., 2014.

Charlesworth, David, Bill D’All, Cecile Zimmerlin, Elias Remita, Nina Langhelle,, and Ting Wang, “Operational Experience of the Fatigue Performance of a Flexible Riser with a Flooded Annulus,” Offshore Tech-nology Conference, Rio de Janeiro, Brazil, 4–6 October 2011.

Dupoiron, Francois and Carol Taravel Condat, (2003, January 1). “High Strength Metallic Materials for Flexible Pipes: Specific Environments and Corrosion Behavior,” NACE International: CORROSION 2003, San Diego, California, 16–20 March 2003.

Last, Sijm, Steve Groves, Jean Rigaud, Carol Taravel- Condat, Jakob Wedel-Heinen, Richard Clements, and Stefan Buchner, “Comparison of Models to Predict the Annulus Conditions of Flexible Pipe,”Offshore Technology Conference, Houston, Texas, 6–9 May 2002.

Usage Shares
Total Views
103 Page Views
Total Shares
1 Tweets
0 PDF Downloads
1 Facebook Shares
Total Usage