DETERMINING THE VISCOSITY OF A HYDROCARBON RESERVOIR FLUID

摘要

Deteriming the viscosity of a hydrocarbon reservoir fluid that is present in a formation layer traversed by a borehole, which method comprises the steps of selecting a location in the formation layer; lowering in the borehole to the location a tool that comprises a central conduit having an inlet, means for displacing fluids through the central conduit, and an optical fluid analyser; making an exclusive fluid commuication between the formation and the inlet of the central conduit; obtaining a spectrum of the optical density; calculating a first factor that is the maximum optical density in a predetermined short-wavelenght range multiplied with the length of the short-wavelenght range, calculating a second factor which is the integral over the same short-wavelength range of the spectrum, subtracting the second factor from the first factor to obtain a hydrocarbon oil porperty; and obtaining the magnitude of the in situ viscosity from the oil property using a relation that had been obtained by fitting a curve (1) through previously obtained data points (2, 3, 4, 5) comprising the measured magnitude of the actual viscosity as a function of the oil property.