Development and Trial of Microwave Techniques for Measurement of Multiphase Flow of Oil, Water and Gas

Abstract

A prototype microwave and gamma-ray MFM has been developed for measurement of oil, water and gas flowrates on production pipelines and has been successfully trialed at the Thevenard Island oil production facility. The microwave and gamma-ray MFM determined the oil and water flow rates with errors of 5.4 and 5.9% relative respectively for the wide range of wells and flow conditions during the trial period. A prototype non-intrusive microwave MFM is being developed for measurement of oil, water and gas flow rates on production pipelines. The microwave MFM will be trialed on the West Kingfish platform in Bass Strait in late 1994. Introduction Crude oil extracted from geological reservoirs is normally accompanied by gaseous hydrocarbons and water. These three components are piped from the oil well as a multiphase mixture. The flow rate measurement of the oil, water and gas from individual wells is important for better reservoir management and optimisation of the total oil production over the field life. The current practice for the measurement of the flow rate of the oil, water and gas components of the multiphase mixture is to periodically physically divert the well output to a test separator. After separation, the flow rate of each component is measured with conventional devices such as orifice plates or turbine flow meters. There are a number of inherent disadvantages with this approach. Firstly, due to cost, a single test separator usually monitors a large number of wells, and therefore it is not possible to continuously monitor the output of each well. In addition the time to monitor a single well can be quite long due to the need to obtain stabilised flow during the test. These factors combined result in infrequent testing of component flows from wells, and potentially less than optimum management of the oil reservoir. Further, the test separator and its associated equipment may contribute significantly to the cost of an off-shore platform. For the purposes of reservoir management, the oil industry requires a multiphase flow meter which is compact and capable of measuring the flow rates continuously to within about 5-10% relative. P. 681^

Microwave sensors for the non-invasive monitoring of industrial and medical applications

“…The object to be measured is put between the antennas in such a way that the microwaves pass through the object. The attenuation or the phase shift of the resonant frequencies are measured (Gainsford and Hide, 1993;Ashton et al, 1994). Importantly, this configuration does not disturb the flow of the oil (i.e.…”

Optimised mode selection in electromagnetic sensors for real time, continuous and in-situ monitoring of water cut in multi-phase flow systems

“…Oon et al [15] utilised the resonant frequencies occurring in a cylindrical cavity to monitor the changes in the permittivity of the measured phases to differentiate between the volume fractions of air, water and oil, however their work focused only on stratified flow. Ashton et al [16] proposed a prototype non-intrusive microwave multiphase flow meter for measurement of oil, water and gas flow rates on production pipelines, focusing on large water-cut values ranging from 25.4% to 95.6%. Hogan et al [17] developed a real-time, non-intrusive multiphase dielectric meter capable of measuring the dielectric properties of different mixtures of oil, gas and water in full well stream flow, but this sensor could not be used in annular or churn flow.…”

“…These early application efforts produced promising results but also highlighted a number of areas requiring further study in order to understand the advantages and limitations of microwave sensors when used to monitor multiphase flow systems. The limitations/industrial drivers identified are related to: utilising the sensors during continuous flow and different flow regimes [13][14][15], the ability to accurately determine low water cuts [16], expansion of the measurement technique to non-homogenous systems [17], the large experimental errors resulting from certain configurations [18], the need to perform volumetric measurements [19] and the consideration of the influence of parameters such as temperature and salinity that can affect the measurements [20].…”

Experimental study on a feasibility of using electromagnetic wave cylindrical cavity sensor to monitor the percentage of water fraction in a two phase system

“…It is acknowledged that MPF meters could bring benefits to the oil and gas industry in terms of layout of production facilities, reservoir management, regular monitoring, production allocation and well testing [9]. Ideally multiphase flow meter should be accurate, reliable, non-intrusive, compact and capable of measuring the flow rates continuously to within 5-10% of error [10]. Figure 1 shows the implementation of MPF meters in an offshore oil and gas production that involves several adjacent wells.…”

“…Over the past two decades, many researchers have developed different measurement techniques to measure the extraction rates of oil and gas [9]. These include gamma-rays [18], microwave [10], impedance techniques [19] and tomography process [20], which are expensive and inaccurate [8]. The electric impedance technique relies on direct current method to measure the resistance of the fluid.…”