Viscosity measurements of liquids under pressure by using the quartz crystal resonators

Jean-Luc Daridon (1) , Marc Cassiède (1) , Jean H. Paillol (2) , Jérôme Pauly (1)

1 LFCR - Laboratoire des Fluides Complexes et leurs Réservoirs
2 LGE

A quartz crystal viscometer has been developed for measuring viscosity in liquids under pressure. It employs an AT-cut quartz crystal resonator of fundamental frequency 3 MHz inserted in a variable-volume vessel designed for working up to 80 MPa. Viscosity is determined by two methods from resonance frequency and bandwidth measurements along up to eight different overtones. The resonance frequency allows an absolute measurement of the viscosity but leads to an accuracy limited to 5% whereas the bandwidth technique which works in a relative way provides an accuracy of 2%. The techniques were tested by carrying out measurements in two pure compounds: heptane and toluene. Measurement results demonstrate the feasibility of the technique in this viscosity range. The apparatus was also used to determine the viscosity of n-decane with dissolved methane. The results obtained with these mixtures reveal the applicability of the apparatus for reservoir fluids study.

Keywords: Absolute measurements; AT-cut quartz crystals; Bandwidth measurements; Dissolved methane; Fundamental frequencies; Measurement results; N-decane; Pure compounds; Quartz crystal; Quartz crystal resonator; Reservoir fluid; Resonance frequencies Engineering controlled terms: Bandwidth; Methane; Modulators; Natural frequencies; Paraffins; Quartz; Toluene; Viscometers; Viscosity; Viscosity measurement Engineering main heading: Crystal resonators

Domains: Chemical Physics [physics.chem-ph]

Jean-Luc Daridon, Marc Cassiède, Jean H. Paillol, Jérôme Pauly. Viscosity measurements of liquids under pressure by using the quartz crystal resonators. Review of Scientific Instruments, 2011, 82 (9), pp.Article number 095114. ⟨10.1063/1.3638465⟩. ⟨hal-00683972⟩