Tiago P. Vendruscolo

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

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.

Development of NIR optical tomography system for the investigation of two-phase flows

Two-phase flows are present in many processes in nature as well as in industrial activities such as exploration, production and transportation of oil and gas. In many cases, flow monitoring determines the efficiency and safety of processes and equipment. Thus, this paper presents a preliminary study about developing an optical tomography system for real-time monitoring of gas-liquid two-phase flows. The system comprises 16 optical sources and 16 optical receivers operating at near-infrared wavelength. Time response of single channels is optimized allowing for fast frame rate measurements up to 1000 frames/s. Initial tests in a two-phase flow loop show promising results.

Capacitive Multielectrode Direct-Imaging Sensor for the Visualization of Two-Phase Flows

In this paper, a novel capacitive array–sensor to visualize two-phase flow by measuring liquid holdup in pipe cross-section is introduced. The measuring principle is based on the difference between electrical permittivity of the phases. The sensor consists of two copper rings being an emitter and one receiver ring. The receiver ring is divided into segments, which are individually interrogated by the measuring electronics in a fast manner. In this way, flow images are directly generated from acquired signals of electrodes in a way that it visually represents the investigated flow, avoiding the use of image reconstruction algorithms as usual in tomographic techniques. The sensor is fabricated in a flexible printed-circuit board, which is flush-mounted in the inner pipe wall. A measuring electronics is responsible to detect the capacitance changes in the electrodes. The introduced sensor along with the associated electronics has been tested in static and dynamic two-phase flow, both horizontally and vertically. Direct images were generated in these different situations, showing satisfactory results when compared with a reference wire-mesh sensor.

Capacitive direct-imaging sensor for two-phase flow visualization

This paper introduces a direct-imaging sensor based on multiple capacitance (permittivity) measurements. The sensor is fabricated in a flexible printed-circuit board (PCB) technology and comprises a driving ring electrode and a number of detecting electrodes flush-mounted into pipe peripheral. Direct images are generated representing the cross-sectional distribution of the phases in a two-phase flow. A prototype sensor was built and the system was tested in three different ways. Firstly in an air-water stratified mixture, secondly in an air-oil stratified mixture and then in a dynamic two-phase flow. Results were compared with a reference sensor showing good agreement.

Multiphase flow parameter estimation based on laser scattering

The flow of multiple constituents inside a pipe or vessel, known as multiphase flow, is commonly found in many industry branches. The measurement of the individual flow rates in such flow is still a challenge, which usually requires a combination of several sensor types. However, in many applications, especially in industrial process control, it is not necessary to know the absolute flow rate of the respective phases, but rather to continuously monitor flow conditions in order to quickly detect deviations from the desired parameters. Here we show how a simple and low-cost sensor design can achieve this, by using machine-learning techniques to distinguishing the characteristic patterns of oblique laser light scattered at the phase interfaces. The sensor is capable of estimating individual phase fluxes (as well as their changes) in multiphase flows and may be applied to safety applications due to its quick response time.

Optical imaging of air and water bubbles flowing through oil

The feasibility of optically detecting air and water bubbles flowing through the oil is presented. By scanning wavelengths it is possible to add functionalities by implementing a spectroscopy based chemical detection that can directly lead to chemical detection and imaging and/or chemical species tomography of flowing fluids. In this article, a halogen lamp (175 - 1000 W and centered at 1.2 mm) and an IR-array camera (8-12 μm, 31 x 32 pixels and 10 fps) is used to observe the three-phase flow involving oil, air and water.

Mid-infrared optical tomography for imaging through petroleum: A feasibility study

The feasibility of generating tomographic images of objects inside crude oil is investigated in this paper. Crude oil in the visible spectrum usually appears as black oil. Nevertheless, in the mid-infrared range, crude oil presents bands of high transmission. These windows of opportunities are explored to obtain data for generating cross-section images. In this paper, a first generation tomograph (containing one radiation source and one detector) is setup and applied to visualize objects inside a typical crude oil sample from a Brazilian reservoir. Reconstructed images based on standard filtered back-projection algorithm for phantom measurements show very promising results.

Two-phase flow measurement based on oblique laser scattering

Multiphase flow measurements play a crucial role in monitoring productions processes in many industries. To guarantee the safety of processes involving multiphase flows, it is important to detect changes in the flow conditions before they can cause damage, often in fractions of seconds. Here we demonstrate how the scattering pattern of a laser beam passing a two-phase flow under an oblique angle to the flow direction can be used to detect derivations from the desired flow conditions in microseconds. Applying machine-learning techniques to signals obtained from three photo-detectors we achieve a compact, versatile, low-cost sensor design for safety applications.