Patent ID: 6508105
Filing Date: 2003-01-21
Classification: G01N

Abstract:
A method of determining the shear threshold of a drilling mud, comprising the steps of placing a detecting head with a spherical surface near a porous wall in a measuring cell, pouring the drilling mud into the cell around the detecting head, forcing mud to pass through the porous surface to form a mud cake above the porous surface and around the detecting head and measuring both the time required for the mudcake to reach a measurable or predetermined height and the torque opposing rotation of the detecting head corresponding to said height, characterised in that during measurement, the inside of the cell is maintained at a predetermined pressure and temperature and the measured time is the time for a compact mudcake to reach the measurable or predetermined height and the torque is measured at this time, this time and torque being used to calculate the shear threshold of the drilling mud.