Research on strain measurement of abyssal riser with FBG sensors

Marine riser fatigue damage in the hostile ocean environments is the fatal issue for deep and ultra deep waters petroleum and gas drilling and productions during. Strain detecting provides a direct measure of the riser fatigue. One riser fatigue monitoring formula based on FBG sensor with orthogonal distribution was researched which takes into account temperature compensation function. Mathematical model for calculating stress and bending moment of riser with the relative change in the Bragg wavelength was presented. One riser stress-strain measuring device based on FBG sensor was designed. Strain measurement tests of a riser scale model were performed. The study shows that the riser fatigue monitoring formula based on FBG sensor presented in this paper is reasonable, and the research results provide the technical support for field practice.