Patent ID: 9568408
Date: 2017-02-14
CPC Classifications: E21B,G01N

Claim:
1. A method comprising: measuring an apparent viscosity of a drilling fluid at a first set of reference conditions comprising a first reference temperature and a first reference pressure, at a second set of reference conditions comprising a second reference temperature and a second reference pressure, and at a third set of reference conditions comprising a third reference temperature and a third reference pressure; wherein at least two of the reference temperatures are substantially equal to one another and at least two of the reference pressures are substantially equal to one another, the reference temperatures and the reference pressures defining a calibration range; determining a rate of change in apparent viscosity with respect to temperature between two of the sets of reference conditions in which the reference pressures are substantially equal; determining a rate of change in apparent viscosity with respect to pressure between two of the sets of reference conditions in which the reference temperatures are substantially equal; and scaling a rheological quantity measured at an initial set of temperature and pressure conditions within the calibration range to a final set of temperature and pressure conditions within the calibration range, the scaling being calculated based upon the rate of change in apparent viscosity with respect to temperature and the rate of change in apparent viscosity with respect to pressure, thereby determining a calculated rheological quantity.