Apparatus and methods of determining fluid viscosity

摘要

Various embodiments include apparatus and methods of determining the viscosity of a fluid downhole in a well. A parameter of a response signal, obtained from driving a tube containing a fluid with an excitation signal for vibrating the tube, can be collected while maintaining the tube in a vibrating mode. The parameter can be evaluated to measure the viscosity of the fluid. In various embodiments, the fluid viscosity may be measured in-situ downhole in the well.

主权项

1. A method comprising:
applying a modulated drive signal to a vibrating tube in a well, the vibrating tube containing fluid from the well, the modulated drive signal being a base signal at a first frequency modulated by another signal at a second frequency, the second frequency being lower than the first frequency; determining a change in a response signal sensed from the vibrating tube, the response signal generated in response to the modulated drive signal applied to the vibrating tube, the determined change in the response signal correlated to the modulated drive signal; and determining viscosity of the fluid from a calculated function of viscosity with respect to change in response signal, the calculated function generated from standard fluids with known viscosity.