Experimental investigation of wet gas over reading in Venturi

• Dimensional analysis is used to establish wet gas measurement correlation.
• Liquid flow rate is unnecessary in this correlation.
• The relative deviations are less than ±1% in laboratory test.
• After modification, the relative deviations are better than ±1% on-site.

In the present age, wet gas measurement is playing an increasingly significant role in the oil and gas industry. Venturi, a classic single-phase flow meter, proved to be a reliable and accurate wet gas flow meter, but it requires correction. Finding a simple wet gas model of Venturi for all possible applications is a common target of researchers and engineers. In this paper, a double differential pressure Venturi is used to reveal the flow characteristics of wet gas and establish a more accurate correlation that performs well in laboratory and on-site tests. Based on a dimensionless analysis and the experimental data, the essential dimensionless groups in wet gas including the differential pressure ratio, gas liquid density ratio, gas Froude number and Lockhart–Martinelli parameter are studied. By using these crucial parameters, the wet gas correlation is established. The results of the laboratory experiment in the Tianjin University wet gas test loop indicate that the relative deviations of this correlation are better than ±1% and that the standard deviation is 0.34%. Despite the different working conditions of a laboratory and the Tarim oilfield, the usage of the wet gas correlation exhibits a system deviation of 18% and a small dispersion. Thus, after the modification, the relative deviations of cumulative flow are all less than ±1%. There is no denying that this wet gas correlation promotes the development of a widely used correlation to a certain extent and benefits other researchers in wet gas measurement.