Sensor distribuído de impedância de dupla modalidade para monitoramento e caracterização de escoamento multifásico

Abstract

Electrical impedance sensors can aid in understanding industrial processes, including substance detection, monitoring, and characterization, such as multiphase flow studies in the oil and gas industry. This study outlines the development of a distributed impedance sensor system designed for the purpose of process investigation, including its development steps, thought process for each subsystem, and decisions regarding the design. The proposed implementation is based on a dual-modality approach where the impedance magnitude is measured at lower frequencies by a programmable excitation source coupled with a discrete resistive transimpedance amplifier (R-TIA) circuit. Additionally, the sensor capacitance is quantified by observing the resonant frequency shift of an LC Tank parallel to the unknown impedance using a capacitanceto-digital converter working at higher (MHz) frequencies. These techniques are employed reciprocally, resulting in a more thorough and descriptive characterization of the sample being tested. This approach helps to overcome the ambiguity and complexity of the impedance response of multiphase mixtures, enabling differentiation between fluid phases in some scenarios. An additional element that adds to the complexity of this application is the fast rate at which changes occur. In order to address this challenge, the sensor sampling rate has been refined to target transients within the millisecond range, which allows for the analysis of a wider variety of multiphase flow scenarios. The system was designed with the goal of distributed sensing and real-time monitoring, evaluating fluid properties during flow and multiphase flow behaviour in transport lines and wells. It enables multiple sensing nodes to connect in a network, allowing simultaneous monitoring at different locations of a pipeline or experiment. A dedicated sensor configuration and data acquisition software was developed to ensure efficient management and real-time inspection of measurements. A separate centralized application was also devised to handle and store the large amounts of data being streamed by the sensors, providing a robust framework for data analysis. The comparison with commercial reference instruments and other measurement techniques shows the applicability of the developed system for the distributed measurement of multiphase flow parameters. Furthermore, the system was used and validated in experimental applications related to flow assurance, such as monitoring fluid displacement (flush) and injection of thermodynamic inhibitors to prevent hydrate formation. This approach enhances understanding and monitoring capabilities in industrial processes, particularly in complex multiphase flow environments within the oil and gas industry.