Intermittent slug flow identification and characterization from pressure signature

Abstract Despite of its occurrence in several industrial applications, it remains an open issue to accurately predict the behavior of multiphase flow. More specifically, when direct observation of the flow is not possible, which typically occurs in the petroleum industry, indirect methods of identifying main features of the flow are necessary. In this paper, we propose a method for the determination of some important parameters in two-phase gas–liquid flow, the velocity in situ of the Taylor Bubble, using differential pressure measurements. This is done through the analysis of the time and frequency signature of a normalized signal and its coupling with void fraction waves. A phase difference estimator based on the cross-spectra between differential pressure signals is proposed. It is experimentally shown that there is a region of the spectrum where the differential pressure signals and the void fraction kinematic waves are coupled. Besides, a relation between the differential pressure signals and the void fraction wave is established, allowing to discuss the underlying physics of the two-phase flow and then determining the Taylor bubble velocity. In this paper, results are shown for intermittent slug flow only, but the proposed approach can potentially be extended to different flow patterns. The presented results show that the use of differential pressure measurements related to void fraction waves have the potential of becoming a methodology applicable by the industry as a tool to identify and characterize flow patterns.