Determination of wax deposition and corrosion in pipelines by neutron back diffusion collimation and neutron capture gamma rays

Wax deposition in pipelines can be very costly for plant operation in oil industry. New techniques are needed for allocation and thickness determination of wax deposits. The timely removal of wax can make large saving in operational cost. Neutron back diffusion and neutron capture gamma rays were used in this study to measure paraffin, asphalt and polyethylene deposition thicknesses inside pipes and to enable simultaneous determination of scale and pipe corrosion. It was possible to determine a thickness change of less than one mm in 2 min. It was also possible to detect localized scale from a small region of the pipe of approximately 2 cm in diameter. Although experiments were performed in lab, the system can be made portable for field applications.

► Paraffin, asphalt and polyethylene deposits inside pipes were measured by neutron back diffusion; change of few mm in thickness was possible. ► It was possible to measure general as well as localized deposit. ► Deposits and pipe wall thicknesses were determined simultaneously by neuron-capture gamma ray. ► Measurements were made from one side of the object; access is not needed on the other side like in radiography. ► The system works for small and large pipes as well as for tanks.