Development of an instrumented riser joint

An instrumented riser joint (IRJ) to continuously record stresses, mud pressures, and mud temperatures was designed for a 24-in. riser operating 500 m water depth, and was installed on a drilling vessel in the North Sea. The IRJ measures axial force (Fz) and bending moments (Mx and My). Design specifications are F = 2.75 MN and Mx and My = 350 kn m, the inaccuracy is 1 %. Field tests and correlation of IRJ output with environmental and vessel motion data show that the IRJ gives reliable output, although due to the laminar flow of the mud in the riser, the temperature indicator does not measure the average mud temperature.