A microwave cavity resonator sensor for water-in-oil measurements

Abstract

Online monitoring of Water-Liquid Ratio (WLR) in multiphase flow is key in petroleum production, processing and transportation. The usual practice in the field is to manually collect offline samples for laboratory analysis, which delays data availability and prevents real time intervention and optimization. A highly accurate and robust sensing method is needed for online measurements in the lower end of WLR range (0%-5%), especially for fiscal metering and custody transfer of crude oil, as well as to ensure adequate flow assurance prevention and remedial solutions. This requires a highly sensitive sensing principle along with a highly precise measurement instrument, packaged together in a sufficiently robust manner for use in the field. In this paper, a new sensing principle is proposed, based on the open-ended microwave cavity resonator and near wall surface perturbation, for non-intrusive measurement of WLR. In the proposed concept, the electromagnetic fringe field of a cylindrical cavity resonator is used to probe the liquid near the pipe wall. Two of the cylindrical cavity resonance modes, TM010 and TM011 are energized for measurements and the shift in the resonance frequency is used to estimate liquid permittivity and the WLR. Electromagnetic simulations in the microwave frequency range of 4 GHz to 7 GHz are used for proof-of-concept and sensitivity studies. A sensor prototype is fabricated and its functionality demonstrated with flowing oil-water mixtures in the WLR range of 0-5%. The frequency range of the proposed sensors is 4.4-4.6 GHz and 6.1-6.6 GHz for modes TM010 and TM011, respectively. The TM011 mode shows much higher sensitivity (41.6 MHz/WLR) than the TM010 mode (3.8 MHz/WLR). The proposed sensor consists of a 20mm high cylinder, with a diameter of 30mm and Poly-Ether-Ether-Ketone (PEEK) filler. The non-intrusiveness of the sensor, along with the high sensitivity in the resonance shift, makes it attractive for practical applications.

Analysis and investigation of a novel microwave sensor with high Q-factor for liquid characterization

“…The results show that the proposed sensor has the highest Q-factor compared to the recently proposed sensors in Table 3. Planar split ring resonator 525 [6] Complementary split ring resonator 80 [7] Planar symmetrical split ring resonator 652 [10] Planar ring resonator 146.67 [11] Substrate Integrated waveguide 334.6 [12] Cavity Substrate Integrated Waveguides ≈300 [13] Re-Entrant cavity waveguide 1190 [14] Multiresonance rectangular cavity waveguide 2605 [15] Circular cavity resonator waveguide 47 [24] Planar split ring resonator 506 [25] Multiple split ring resonator 430 Proposed sensor Gap waveguide cavity resonator 4832…”

“…However, the disadvantage of these sensors is the low Q-factor, which reflects the low sensitivity. Therefore, some researchers tend to use a metal waveguide to increase the Q-factor and sensitivity [13][14][15].…”

High sensitivity simple structured displacement sensor using corrugated substrate‐integrated waveguide (CSIW)

“…As a result, many types of microwave sensors are introduced in different research studies such as industrial sensors that are used in many fields especially in the detection of the characteristics of material due in variation of the permittivity constant [2], detection of gaps in concrete [3], humidity sensor [4], gas detection sensor [5], one-dimensional (1D) and 2D linear and circular displacement microwave sensors [6][7][8][9][10][11][12][13][14].…”

A Visual Measurement of Water Content of Crude Oil Based on Image Grayscale Accumulated Value Difference

“…In 2009, a method for the determination of water content in crude oil mixture by microwave technology was proposed by Makeev et al [5,6]. Sharma et al did more research on this method to a high degree [7]. In 1995, García-Golding et Al.…”