Michael John Black

High Salinity Permittivity Models for Water Cut Sensing

In high salinity water cut measurements, it is observed that the measurement breaks down as a result of the conductivity signal swamping the capacitive signal. An accurate parameterizable model of high salinity permittivity is required for the development of downhole high salinity water cut meters that will operate in reservoir brine conditions in the 100 000 ppm to 200 000 ppm range. Theoretical models proposed by Stogryn Meissner and Wentz, and Somaraju and Trumpf are compared against high salinity data obtained by Peynman An effective temperature correction accounting for the influence of salinity-induced viscosity variations on permittivity is devised. This improves the fit to the real component of permittivity within the salinity range of interest: the Meissner and Wentz model provides the best fit. Subsequently, additional mechanisms need to be considered to account for the global mismatch between theory and experiment.

Energy transfer and motion synchronization between mechanical oscillators through microhydrodynamic coupling

Fluidic environment is encountered for mechanical components in many circumstances, which not only damps the oscillation but also modulates their dynamical behaviors through hydrodynamic interactions. In this study, we examine energy transfer and motion synchronization between two mechanical micro-oscillators by performing thermal lattice-Boltzmann simulations. The coefficient of inter-oscillator energy transfer is measured to quantify the strength of microhydrodynamic coupling, which depends on their distance and fluid properties such as density and viscosity. Synchronized motion of the oscillators is observed in the simulations for typical parameter sets in relevant applications, with the formation and loss of stable anti-phase synchronization controlled by the oscillating frequency, amplitude, and hydrodynamic coupling strength. The critical ranges of key parameters to assure efficient energy transfer or highly synchronized motion are predicted. These findings could be used to advise mechanical design ...