Dual-modality wire-mesh sensor for the visualization of three-phase flows

Abstract

Three-phase gas–liquid–liquid flows are very common in petroleum extraction, production, and transport. In this work a dual-modality measuring technique is introduced which may be well applied for three-phase flow visualization. The measuring principle is based on simultaneous excitation with two distinct frequencies to interrogate each crossing point of a mesh sensor, which in turn are linked to conductive and capacitive parts of fluid impedance. The developed system can operate eight transmitter and eight receiver electrodes at a frame repetition frequency up to 781 Hz. The system has been evaluated by measuring reference components. The overall measurement uncertainty was 8.4%, which considering the fast repetition frequency of measurements is suitable for flow investigation. Furthermore, a model-based method to fuse the data from the dual-modality wire-mesh sensor and to obtain individual phase fraction of gas–oil–water flow is introduced. Here a parametrized model is fitted to the measured conductivity and permittivity distributions enabling one to obtain phase fraction from measured data. The method has been applied and tested to the acquired data from a mesh sensor in static and dynamic three-phase mixtures of gas, oil, and water. Fused images and quantitative values show good agreement with reference values. The newly developed dual-modality wire-mesh sensor has the potential to investigate three-phase flows to a good degree of detail, being a valuable tool to investigate such flows.

Fuzzy Logic Based Multi-Dimensional Image Fusion for Gas–Oil-Water Flows With Dual-Modality Electrical Tomography

“…Since the concentration values are continuously distributed within the range [0,1], colours have to be continuous when mapping the vectors to colours, and thus a triangle RGB colour space has to be considered. In this paper, a triangle RGB colour space similar to the one in [10] is employed for the mapping and displaying, as depicted in Fig. 8.…”

“…As far as the measurement and visualisation of gas-oil-water flow by DMTS are concerned, the research is still at its early stage, and the majority of the attention has been paid to the hardware, e.g. integrating different sensors together [8]- [10]. Among exsiting DMTS, ERT-ECT systems are a particular example characterised by low-cost, non-intrusive/invasive and non-radioactive electrical tomography.…”

“…Using thresholds to determine geometrical distributions of gas-oil-water flow is the predominant method for DMTS to visualise gas-oil-water flow [10], [13], [17], [19]. In the threshold method, the original images are binarised by different threshold values which are usually modality specific.…”

Characterizing the correlations between local phase fractions of gas–liquid two-phase flow with wire-mesh sensor

“…Based on the sensitive dielectric properties of the fluid, the WMS can be divided into two modalities: conductance WMS [3] and capacitance WMS [4]. These two modalities can be combined to form a dual-modality WMS for three-phase flow monitoring [5]. The measurement principle of WMS has also been applied to temperature field reconstruction by replacing the electrodes with temperature mesh sensors [6]; the temperatures were measured by thermocouples placed in the crossing points of transmitters and receivers.…”

Capability of dual-modality electrical tomography for gas-oil-water three-phase pipeline flow visualisation

“…Reported evaluations have been conducted using either simulation techniques or simple flow structures, e.g. stratified flow [6,8,13]. Although Yue et al have assessed their ERT-ECT systems for several flow regimes in laboratory-scale gas-water two-phase flow facilities, for a variety of stratified flow, slug flow, and plug flow, the capability of systems for extensive flow regimes of gas-oil-water flow is still unknown.…”