Investigation of a microwave tomographic system for oil and gas multiphase flow imaging

Since the 1980’s, electrical tomographic imaging techniques based on low frequency capacitance, resistance or inductance measurements have been developed for the monitoring of various industrial processes, and also in some cases to oil and gas multiphase flows. The research of microwave tomography for oil and gas multiphase flow imaging began in the mid 1990’s even though the basic principle of microwave tomography was reported a decade earlier. Microwave tomography in principle would produce higher resolution images than low-frequency imaging techniques. In addition to multiphase flows, the microwave technique has been investigated over the past two decades for medical imaging with some degree of success. In this paper, an experimental microwave tomography system is described for potential application for oil and gas flow imaging. This includes the laboratory hardware for data acquisition and the iterative algorithm for image reconstruction. The results of using the system for tomographic imaging of oil-gas flow distributions are presented and compared using two different operating frequencies. The quality of the microwave tomographic imaging at different frequencies is then assessed, which shows that better images are reconstructed at the higher frequency.