Bending strain is the main contributor to fatigue damage in the touch-down zone (TDZ) of a Steel Catenary Riser (SCR). Measurement of the curvature in the SCR at the TDZ due to bending is essential to the validation of numerical models for SCR response and fatigue estimation. Long term SCR integrity monitoring systems may also require tools for the measurement of bending strain in the TDZ. In deep water, production SCRs typically have thick anti-corrosion and insulation layers that make the inference of the strain in the underlying pipe challenging. This paper describes the development of a strain measurement system and unique attachment scheme that can be literally built into the insulation and anti-corrosion layers on ultra deep water SCRs. Results of qualification tests will be presented that prove that the “insulation strain measurement system” produces a very accurate estimate of the strain in the underlying pipe steel. In addition, test results are presented that demonstrate that the attachment scheme does not threaten the integrity of the insulation and corrosion protection layers. Finally full scale bending strain measurement results will be presented from the TDZ of the Total AKPO Gas Export SCR in 1200 meters of water that illustrate the quality of the data, the excellent resolution and reasonableness of the results compared to numerical model predictions.
展开▼
