Characterization of oil/water two-phase flow patterns based on nonlinear time series analysis

Abstract

The flow patterns of oil/water two-phase flow in vertical upward pipes have been characterized by the analysis of fractal, chaos and Kolmogorov entropy based on the conductance time series fluctuating signals. It is shown that the fractal, chaotic dimensions and Kolmogorov entropy all have a good correlation with the total flow rate ( Q t) and water cut ( K w) for the flow conditions of 61%≤ K w≤91%,10 m 3/d≤ Q t≤60 m 3/d; for K w=51%, they show irregular sudden changes, which correspond to changes in the transitional flow pattern and is strongly supported by the characteristics of the complex power spectrum. It is concluded that the dimensions and the entropy are sensitive ‘indicators’ of flow pattern variations.