In multiphase flow, the velocity differences between phases means unless the velocities of individual phases and concentrations are known, the true flow rate is practically impossible to obtain. At present, there is no single multiphase flow meter design capable of providing the required accurate measurements of oil, water, and gas fractions, as well as the phase velocities of wet gas. This research thesis introduces a prototype multi-phase flow metering system, named Uletechement. The main objectives of this research is to provide individual phase velocities of wet gas, and to combine with phase volume fraction measurements to obtain individual phase volume flow rates for gas and liquid Hydrocarbon (HC). The system comprised of a camera, laser source, synchronizer, computer data acquisition system and MATLAB based software, gas liquid chromatograph, seeds and tracer injecting devices. The gas-phase velocity is determined based on Particle Imaging Velocimetry (PIV). An algorithm that correlates the cameradeveloped through this research. The computer acquires two sequential image signals from the camera, and carries out the calculation of cross correlation between the images so that the average particle displacement within each interrogation area can be found. The average gas-phase velocity is subsequently obtained by integrating pixel velocity along the distance between two image frames obtained by a Charged Couple Device (CCD) camera. The product of phase velocity and phase concentration gives the flow rate of gas phase. The HC condensate flow is measured by injecting the fluorescent tracer - Silicone Carbide (SiC) at a known flow rate, which mixes only with the condensate. By sampling and analyzing samples further downstream, the ratio of the fluorescence of the injected and sampled condensates are subsequently determined. And the HC condensate flow rate can then be derived. The proposed method has been tested using a rig at Shell laboratory for the samples with a range of phase fractions and at several different velocities and flow rates. Due to the limitation of the rig, simultaneous measurement of the gaseous and condensate flow rate could not be done. But the experiments for liquid HC and gaseous phase measurements were carried out separately. However, this did not devalue the validation. The test results have been analysed and provided in the thesis, which confirmed the concept of proposed method.
|Date of Award||15 Mar 2013|
|Supervisor||Jianyong Zhang (Supervisor)|