Two-phase flow metering of heavy oil using a Coriolis mass flow meter: A case study

Abstract

The use of Coriolis mass flow metering for two-phase (gas/liquid) flow is an emerging theme of both academic research and industrial application. The key issues are maintaining flow-tube operation, and modelling and correcting for the errors induced in the mass flow and density measurements. Experimentally-derived data is used to illustrate that these errors vary most notably with gas void fraction (GVF) and liquid flow rate, but other factors such as flow-tube geometry and orientation, and fluid properties such as viscosity are also influential. While undoubtedly a universal two-phase flow correction model is the ultimate research goal, there is currently no obvious candidate to explain the range of behaviours observed. This paper describes and demonstrates an empirical methodology that has proven effective in developing good correction models for a given choice of Coriolis flow-tube and flow mixture.A growing proportion of the world's oil reserves may be described as "heavy", implying high density and high viscosity. Of the various metering challenges heavy oil poses, one of the most significant is its ready entrainment of gas, and the difficulties entailed in separating gas from the oil. Accurate two-phase measurement of heavy oil is therefore an especially desirable technical goal.Trials were carried out at the National Engineering Laboratory (NEL), Scotland on a 75 mm flowmeter using a high viscosity oil. Flowrates from 1 kg/s to 10 kg/s were examined, with gas void fraction (GVF) up to 80%. The resulting models were tested online in a commercial Coriolis mass flow meter and demonstrated good performance for both steady and slugging two-phase flows, with the corrected measurements typically within 1%-5% of the nominal mass flow and density.Field trials in Venezuela have confirmed the performance of this two-phase solution. While research continues into the development of a generic two-phase correction, this case study demonstrates that the current state of the art can provide, for economically important fluids, tailored models with good two-phase flow performance.

Coriolis Mass Flow Metering for Wet Gas

“…Coriolis flow meters have increasingly been used in multi-phase applications, but mostly in low GVF conditions [3] . In providing two process measurements (mass flow and density) the Coriolis meter cannot provide true three-phase metering, except in conjunction with another technology (e.g.…”

A Novel Drive Scheme of Coriolis Mass Flowmeter Based on Adaptive Fuzzy Sliding Mode Control

“…Due to the CMF with analog control scheme is easily effected by ambient temperature and external disturbances, and it has shown poor performance during two-phase flow condition [7][8][9], Shimada develops a digital-analog drive system in [10], where analog module is used for the startup of the flow tube and digital module is used when the flow tube reaches resonant mode. Based on PI control, Zamora studies an alldigital drive scheme to maintain the resonant mode in the state of two-phase flow in [11].…”

A study on an online measurement method to determine the oil discharge ratio by utilizing Coriolis mass flow meter in a calorimeter

“…Techniques of CMFs have been investigated by continuous theoretical (Sultan and Hemp, 1989;Kazahaya, 2011) and experimental (Liu et al, 2001;Henry et al, 2006) researches in the past decades. Currently, CMFs have been widely accepted in many industrial applications, such as food and beverages, chemical and pharmaceuticals as well as oil and gas fields.…”