Pressure Wave Velocity in Fluid-Filled Pipes with and without Deposits in the Low-Frequency Range

Solid pipeline deposits can be mapped by analyzing reflections of hydraulic pressure pulse waves in the low-frequency range. To determine the amount and position of the deposits, an inverse problem is solved: the pressure pulse is measured in one or several positions, and the pipeline that generated this pulse must be determined. To solve this problem, estimates of the pressure pulse velocity are essential. This study implements a finite-element axisymmetric model for fluid-filled pipelines and applies it to numerically study low-frequency estimates of the pressure wave velocity in pipes with deposits that appear frequently in pipelines of the petroleum industry. Finite-element simulations include deposit thicknesses in the range up to and covering 90% of the internal diameter of the pipe. The results show how deposits with different stiffness affect the pressure wave velocity. Inputs to the model are the geometry and parameters (thickness, Young’s modulus, and Poisson’s ratio) of the pipe and the deposits.