Multiphase flowmeters (MPFMs) have been used since the early 1990's in the oil and gas industry and have gained acceptance in many environments. They have been considered the primary metering option for a wide range of applications - from heavy oil to wet gas. The combination of operational benefits, measurment robustness, demonstrable accuracy, and auditability has improved their status from new, unproven technology to that of the premium mainstream metering option.

With more than a decade of experience acquired using a combination venturi and gamma-ray multiphase flowmeteres, further gains in measuremnet quality and operational robustness have been achieved. We will illustrate how enhancements in fraction measurements using multi-energy gamma ray attenuation and a more comprehensive analysis of the gamma-ray spectrum have been developed and implemented to provide better measurement accuracy and stability, leading to enhanced performances in multiphase flow measurements.

Another area of improvement that has been pursued is in the field of modeling of multiphase flows through a venturi. Historically, single-phase flow equations have been used, being adapted to multiphase flows by semi-empirical means to account for their complexity. While such models have proven robust for most standard applications, they can reach some limitations in particular conditions. We will present how a more dynamic model that considers the nature of the flow has led to improved accuracy of multiphase flow measurements.

We present the scientific basis for the new enhancements as well as illustrate the accuracy gains achieved based on hundreds of flow loop test points, ultimately leading to the quantification of the accuracy gains obtained through those technological improvements.