The Michelsen Center for Industrial Measurement Science and Technology

Bergen, Norway

The Michelsen Center for Industrial Measurement Science and Technology

Bergen, Norway

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Carlson J.E.,University of Bergen | Carlson J.E.,Lulea University of Technology | Carlson J.E.,The Michelsen Center for Industrial Measurement Science and Technology | Tomren A.L.,University of Bergen | And 3 more authors.
Chemometrics and Intelligent Laboratory Systems | Year: 2014

Dielectric properties of crude oils play an important role in characterization and quality control. Measuring permittivity accurately over a wide range of frequencies is, however, a time-consuming task and existing measurement methods are not easily adapted for real-time diagnostics. IR spectroscopy, on the other hand, provides rapid measurements of fundamental molecular properties.In this paper we show that by using multivariate calibration tools such as PLS regression, it is possible to extract dielectric properties of crude oils directly from IR spectra, in addition to conventional interpretation of the spectra, hence reducing the need for direct electrical measurements. Results on 16 different oil samples show that the dielectric parameters obtained with the proposed method agree well with those obtained using direct permittivity measurements. The PLS regression method has also been extended with Monte Carlo simulation capabilities to account for uncertainties in the data. © 2014 Elsevier B.V.


Saetre C.,University of Bergen | Saetre C.,The Michelsen Center for Industrial Measurement Science and Technology | Tjugum S.-A.,The Michelsen Center for Industrial Measurement Science and Technology | Anton Johansen G.,University of Bergen | Anton Johansen G.,The Michelsen Center for Industrial Measurement Science and Technology
Radiation Physics and Chemistry | Year: 2014

Measurement of multiphase pipe flow of gas, oil and water is not at all trivial and in spite of considerable achievements over the past two decades, important challenges remain. These are related to reducing measurement uncertainties arising from variations in the flow regime and the fluid properties, improving long term stability and developing new means for calibration, adjustment and verification of the multiphase flow meters. In this work the pipe flow is split into temporal segments using multiple gamma-ray measurements. One 241Am source with principal emission at 59.5keV was used because this relatively low energy enables efficient collimation and thereby shaping of the beams, as well as use of compact detectors. One detector is placed diametrically opposite the source whereas the second and eventually the third are positioned to the sides so that these beams are close to the pipe wall. The principle is then straight forward, that is to compare the measured intensities of these detectors, and through those identify the instantaneous cross sectional gas-liquid distribution, i.e. the instantaneous flow pattern. By counting the intensity in short time slots of <100ms, experiments verify that rapid variations exist. The water salinity is one of the fluid properties which challenge most multiphase flow meters because its variations affects component volume fraction calculations based on gamma-ray, electrical conductance and other measurements methods. At the University of Bergen a dual modality method has been developed using simultaneous measurements of transmitted and scattered gamma-rays from a 241Am source. This allows the gas volume fraction to be determined independent of changes in the water salinity, provided that the fluid is fairly homogeneously mixed. Tomographic flow segmentation allows selection of low gas fraction segments where the salinity, in combination with running averaging methods, can be calculated with higher accuracy. © 2013 Elsevier Ltd.


Hjertaker B.T.,University of Bergen | Hjertaker B.T.,The Michelsen Center for Industrial Measurement Science and Technology | Maad R.,University of Bergen | Maad R.,The Michelsen Center for Industrial Measurement Science and Technology | And 2 more authors.
6th World Congress in Industrial Process Tomography | Year: 2010

A dual mode tomography system based on electrical capacitance and gamma-ray tomography has been developed at the Department of Physics and Technology, University of Bergen. The objective of the dual mode tomograph is to acquire cross-sectional images, i.e. tomograms, of hydrocarbon flow comprising oil, water and gas constituents.The capacitance tomograph utilizes an eight-electrode sensor set-up mounted around a PVC pipe structure which is sensitive to the electrical permittivity εr of the flow. By using the capacitance tomograph, the produced water constituent can be separated from the gas and crude oil constituents, assuming that the liquid phase is oil continuous. The high speed gamma-ray tomograph comprises five 500 mCi 241Am gamma-ray sources, each at a principal energy of 59.5 keV, which corresponds to five detector modules, each consisting of 17 CdZnTe detectors mounted around the same pipe section as the capacitance sensor. The gamma-ray tomograph discriminates between the gas and liquid phase, since these have different photon attenuation coefficients. As a result, the gamma-ray tomograph is able to distinguish the gas phase from the liquid phase of the hydrocarbon flow. Consequently, the dual mode capacitance and gamma-ray tomography set-up is able to distinguish the oil, water and gas constituents of hydrocarbon flow.This paper presents the work that has been performed related to static characterization of the dual mode tomograph using the Landweber reconstruction algorithm on polypropylene phantoms. The objective of the work has been to quantitatively evaluate the static imaging performance of the dual mode tomograph with respect to relative spatial measurement errors, i.e. root mean square errors of the reconstructed tomograms compared to that of the phantom. The work shows that dual mode tomography using electrical capacitance and gamma-ray sensors is feasible on hydrocarbon flow components using a pixel-to-pixel fusion procedure on separately reconstructed tomograms based on the Landweber reconstruction algorithm. © 2010, International Society for Industrial Process Tomography. All rights reserved.


Johansen G.A.,University of Bergen | Johansen G.A.,The Michelsen Center for Industrial Measurement Science and Technology | Hampel U.,Helmholtz Center Dresden | Hjertaker B.T.,University of Bergen | Hjertaker B.T.,The Michelsen Center for Industrial Measurement Science and Technology
Applied Radiation and Isotopes | Year: 2010

Fourth generation medical X-ray scanners using a gantry with a rotating X-ray source and a fixed circular detector array as sensor head, are too slow for imaging of the process dynamics for instance in multiphase flows. To avoid inconsistent measurements and motion blurring, all measurements need to be carried out in a short time compared to the time constants of the process dynamics. Two different high speed tomographic imaging systems are presented here demonstrating that image rates of several thousand images per second is possible. © 2009 Elsevier Ltd. All rights reserved.


Maad R.,University of Bergen | Maad R.,The Michelsen Center for Industrial Measurement Science and Technology | Hjertaker B.T.,University of Bergen | Johansen G.A.,University of Bergen | Olsen T.,University of Bergen
Flow Measurement and Instrumentation | Year: 2010

A HSGT (High Speed Gamma-ray Tomograph) has been designed and built at the University of Bergen with the objective to monitor rapid changes in multiphase hydrocarbon flow regimes. In order to perform real-time image reconstruction with photon integration times as low as 10 ms, a novel DACS (Data Acquisition and Control System) has been developed. The DACS is based on FPGA (Field-Programmable Gate Array) programming of the CompactRIO module from National Instruments to minimize its data acquisition and control time. The CompactRIO module includes a reconfigurable FPGA, which provides hardware-level data acquisition and control determinism with a time resolution of 25 ns. The data acquisition and control time for the HSGT obtained with the novel DACS interface design is 0.18 ms, which corresponds to a data transmission bandwidth of 1.35 Mbytes/s given that the HSGT data frame consists of 85 channels each comprising a 24 bit resolution. The DACS also facilitates FPGA sensor data pre-processing, i.e. normalization, of the acquired tomograph data to speed up the image reconstruction. Dynamic characterization of the HSGT for rotational and translational movements is presented in this paper, which is based on calculation of the RMSE (Root Mean Square Error) of the acquired tomogram compared to that of the test phantom. The test phantom consists of two spherical holes with different radius in a polypropylene sample. The results of the dynamic characterization show that the HSGT can sustain imaging of a rotational object with angular velocities ~30 rad/s. For translational movement (free fall) the HSGT is able to detect internal cross-sectional structures with velocities up to ~4 m s-1. © 2010 Elsevier Ltd.


Saetre C.,University of Bergen | Saetre C.,The Michelsen Center for Industrial Measurement Science and Technology | Johansen G.A.,University of Bergen | Johansen G.A.,The Michelsen Center for Industrial Measurement Science and Technology | Tjugum S.A.,University of Bergen
Flow Measurement and Instrumentation | Year: 2010

For oil production fields, there is a need for downhole measurements of the gas/water/oil multiphase flow. In extreme conditions a relatively simple, robust, and non-intrusive system will be appropriate. A measurement setup that combines multiple gamma beam (MGB) and dual modality densitometry (DMD) measurements, would be able to determine the gas volume fraction (GVF) independently of the flow pattern, and monitor changes in water salinity. MGB measurements of gamma-ray transmission along multiple sections across the oil pipe will provide information on the flow pattern. Whereas the DMD principle will give information on changes in salinity from a combination of transmission and scattering gamma-radiation measurements. In this work we present the results from MGB and DMD measurements of a multiphase flow with high-speed gamma-ray tomograph measurements as reference for the flow pattern. The MGB measurements should enable us to distinguish between stratified or wavy/slug and annular or slug flow. Flow patterns with several minor components distributed evenly over the measurement cross section, like bubble flow, will be interpreted as homogeneous flow. The DMD measurements can be used to monitor salinity changes of the water component for intervals where the GVF is low and the water cut of the liquid is high. Combined with other gauges for water cut measurements, the MGB and DMD measurement setup should improve the multiphase flow measurements, and enable increased oil/gas recovery and production water monitoring. © 2010 Elsevier Ltd.


Bruvik E.M.,University of Bergen | Hjertaker B.T.,University of Bergen | Hjertaker B.T.,The Michelsen Center for Industrial Measurement Science and Technology | Hallanger A.,Christian Michelsen Research
Flow Measurement and Instrumentation | Year: 2010

Gamma-ray tomography is a technique well suited to visualize gas void fraction distribution in two-phase flows. The liquid phase considered in this paper is a homogeneous mixture of oil and water. Gamma-ray tomography will be used to qualitatively visualize the distribution of gas in the flow, and also to provide more quantitative average void fraction measurements. The subject treatment is practical and experimental with a primary focus on multiphase sampling. Experimental results for total average void fraction are compared to the drift-flux model for two-phase flow by comparing measurements with the calculated slip. © 2009 Elsevier Ltd.


Mazzawi N.,Technion - Israel Institute of Technology | Postema M.,University of Bergen | Postema M.,The Michelsen Center for Industrial Measurement Science and Technology | Kimmel E.,Technion - Israel Institute of Technology
Acta Physica Polonica A | Year: 2015

The bilayer sonophore model suggests that ultrasound induces a pulsating structure in the intra-membrane hydrophobic space between the two lipid monolayer leaflets of the cell membrane, assembled by dissolved gas of the surrounding area, which absorbs acoustic energy and transforms it by creating intra-cellular structural changes. This void has been referred to as a bilayer sonophore. The bilayer sonophore inflates and deflates periodically when exposed to ultrasound and may itself radiate acoustic pressure pulses in the surrounding medium in the same way a gas bubble does: once exposed to ultrasound the bilayer sonophore becomes a mechanical oscillator and a source of intracellular cavitation activity. In this paper, we describe observations of the clustering behaviour of living cells and several other particles in a standing sound field generated inside a ring transducer. Upon sonication, blood cells and monodisperse polystyrene particles were observed to have been trapped in the same locations, corresponding to nodes of the ultrasound field. Because polystyrene is hydrophobic, it behaves like a particle trapped inside a thin gas shell. In fact, the sonophore model treats biological cells in a similar way. Microbubbles that form the ultrasound contrast agent Quantison™ behave differently, however. These microbubbles accumulated in circles faster than blood cells and polystyrene particles. In addition, they form tightly packed clusters at the nodes, indicating very strong secondary Bjerknes forces. Cluster formation is not to be expected in cells with predicted sonophore sizes on the order of 10-100 nm.


Helseth L.E.,University of Bergen | Helseth L.E.,The Michelsen Center for Industrial Measurement Science and Technology
Journal of Colloid and Interface Science | Year: 2012

Complexes of dyes and polyelectrolytes have found widespread use in a variety of functional materials and interfaces. Here it is found that upon mixing the anionic dye pyranine and a cationic polyelectrolyte, poly(allylamine-hydrochloride), two different colloidal structures may form. Above a certain concentration of anionic dye, crosslinking of the polyelectrolyte is initiated, and the formation of sheet-like colloidal structures was observed. Addition of hydroxyl ions resulted in the formation of micron-sized spherical colloids. It was also found that the colloidal shape transition was accompanied by a significant red-shift in the fluorescence emission. Combining fluorescence measurements with studies of the particle size with time, it was found that red-shift was related to the crosslinking of the dye and the polyelectrolyte, and was not influenced significantly by the aggregation and particle growth. Further information about the colloidal behavior and stability was obtained by letting droplets dry and follow the kinetics of this process. It was found that the particles collapsed near the contact line and formed a ring deposit, in agreement with previous studies. However, unlike previous studies, the thickness of the ring deposit did not grow significantly with time, due to the peculiar process of formation found here. © 2012 Elsevier Inc.


Saetre C.,University of Bergen | Saetre C.,The Michelsen Center for Industrial Measurement Science and Technology | Johansen G.A.,University of Bergen | Johansen G.A.,The Michelsen Center for Industrial Measurement Science and Technology | Tjugum S.A.,The Michelsen Center for Industrial Measurement Science and Technology
Applied Radiation and Isotopes | Year: 2012

Measurement of multiphase flow of gas, oil and water is not at all trivial and in spite of considerable achievements over the past two decades, important challenges remain (Corneliussen et al., 2005). These are related to reducing measurement uncertainties arising from variations in the flow regime, improving long term stability and developing new means for calibration, adjustment and verification of the multiphase flow meters. This work focuses on the first two issues using multi gamma beam (MGB) measurements for identification of the type of flow regime. Further gamma ray tomographic measurements are used for reference of the gas/liquid distribution. For the MGB method one Am-241 source with principal emission at 59.5. keV is used because this relatively low energy enables efficient collimation and thereby shaping of the beams, as well as compact detectors. One detector is placed diametrically opposite the source whereas the second is positioned to the side so that this beam is close to the pipe wall. The principle is then straight forward to compare the measured intensities of these detectors and through that identify the flow pattern, i.e. the instantaneous cross-sectional gas-liquid distribution. The measurement setup also includes Compton scattering measurements, which can provide information about the changes in the water salinity for flow segments with high water liquid ratio and low gas fractions. By measuring the transmitted intensity in short time slots (< 100 ms), rapid regime variations are revealed. From this we can select the time sections suitable for salinity measurements. Since the salinity variations change at the time scale of hours, a running average can be performed to increase the accuracy of the measurements. Recent results of this work will be presented here. © 2012 Elsevier Ltd.

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