Abstract: In the application of integrity management of oil and natural gas pipeline, there are some problems about the blocking risk of classical smart PIG and non-detectability of the polyurethane foam PIG. Therefore, the force sensors are mounted on the foam PIG to design a novel smart PIG with low blocking risk and capabilities for deformation detection. Through the theoretical analysis and experiment, it is found that the smart foam PIG can detect the pipe deformation and the result shows a good linear relationship when the deformation is less than 1/2 depth of sensors. Secondly, the detection sensitivity is unrelated to the initial position of sensors in the same density structure of inner and outer layer foam, so that the initial thickness of the inner foam can be reduced to enhance system reliability. And then, for the high inner and low outer density structure, the detection sensitivity can be improved by increasing the initial thickness and density of the inner foam, with attention to the effect on the reliability of the detection system. The novel smart foam PIG can detect and locate the deformation rapidly and safely by reducing the number of pre-pigging and blocking risk.

Key words: pipeline deformation, flexible detection, polyurethane, smart PIG, blocking risk