Chapter 6 Wet Gas Metering Applications

Abstract

This chapter deals with the applications of wet gas metering that can apply to condensate gas fields, high gas–oil ratio fields, and wet gases. Produced streams of wet gas are metered for a variety of reasons: reservoir management, allocation issues, and metering the produced gas only or metering the liquid and the gas, depending on whether one phase or both are to be sold. The pressure–volume–temperature (PVT) characterization of a wet or retrograde gas is carried out based on a molar composition down to the C 20 , as the results of phase behavior models are very sensitive to the heavy end description. The collection of representative fluid samples for the PVT characterization of a wet or retrograde gas remains an issue for the oil and gas industry. PVT characterization based on the recombination of gas and liquid samples from the separator is more likely to capture the actual fluid composition at surface. The wet gas flow metering guidelines by the ASME (2008) provide numerical examples that quantify the sensitivity of wet gas correlations for differential pressure meters to the use of different Lockhart–Martinelli parameter definitions, concluding that the rate prediction errors could be non-negligible. The concept behind the ANUMET meter is that of deducing the liquid flow rate from measurements on annular flow in a straight pipe section, and then using this liquid flow rate in the interpretation of pressure drop data from a venturi placed downstream of the straight pipe section in order to deduce the gas flow rate.