دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: see thxotropy.

n: the property exhibited by a fluid that is in a liquid state when flowing and in a semisolid, gelled state when at rest. Most drilling fluids must be thixotropic so that cuttings will remain in suspension when circulation is stopped.

n: The characteristic of a fluid, such as a drilling mud, to form a gelled structure over time when not subject to shearing and then to liquefy when agitated. The viscosity of a thixotropic fluid changes with time under constant shear rate until reaching equ

n: the resistance to initial flow, or the stress required to start fluid movement. This resistance is caused by electrical charges located on or near the surfaces of the particles. The values of the yield point and thixotropy, respectively, are measurements of the same fluid properties under dynamic and static states. The Bingham yield value, reported in pounds/100 square foot, is determined from a directindicating viscometer by subtracting the plastic viscosity from the 300-rpm reading. Also called yield point.

Also called movable shear stress. The viscosity dont change along with the shear stress when shear stress arrive a given value,now shear stress and rate of shearing present direct ratio relation, the value of crossing point of this direct ratio relation