Measurement Data Processing of the Wet Gas Flow Based on Blind Source Separation Techniques
|School||China University of Petroleum|
|Course||Control Science and Engineering|
|Keywords||slotted orifice wet gas flow metering blind source separation independent component analysis differential pressure correlation|
Wet gas flow is a typical two-phase flow with low liquid fractions. Wet gas metering is a subset of multiphase flow metering, and it is one of the major unsolved problems for oil and gas industry. Recently, more and more signal processing technologies have been used in the data processing of wet gas flow, and it is an important issue for wet gas flow metering.Based on a self developed prototype of wet gas meter and an experimental data set, differential pressure (DP) signals from slotted orifices have been processed from a view of signal separating. Two Blind Source Separation (BSS) techniques, which are BSS based on Time-Frequency analysis (TF-BSS) and Independent Component Analysis (ICA), have been used to extract characteristic quantity of wet gas flow. Gas and liquid flow are acquired at last.This thesis consists of three parts. The first part mainly focuses on the two-phase flow metering based on TF-BSS method; The second part elaborates the metering process based on ICA method; The third part is a comparison and an analysis of these two ways, and a conclusion is given in the end.Based on DP signals from a couple of slotted orifices, TF-BSS (TIFROM algorithm) and ICA (FastICA algorithm) are used to separate different effects respectively. A good relationship between the liquid flow rate and the characteristic quantity of the separated signal is established, and a differential pressure correlation for slotted orifice is applied to calculate the gas flow rate. The calculation results are good with 90% relative errors less than±10%.The results show that BSS is an effective method to extract the effect of the liquid flow from DP signals of wet gas flow, and this provides a new approach of wet gas flow metering.