U-tube viscometers: these devices are also known as glass capillary viscometers or Ostwald viscometers, which consists of a U-shaped glass tube held vertically in a controlled temperature bath. In one arm of the U is a vertical section of precise narrow bore (the capillary). Above there is a bulb, with it is another bulb lower down on the other arm. In use, liquid is drawn into the upper bulb by suction, then allowed to flow down through the capillary into the lower bulb. Two marks (one above and one below the upper bulb) indicate a known volume. The time taken for the level of the liquid to pass between these marks is proportional to the kinematic viscosity.
Rolling ball viscometer:The rolling ball viscometer determines the viscosity of samples collected either down hole or at the surface. It uses the rolling ball principle where the travel time of a piston is used to obtain viscosity data, which are derived from correlation with curves of fluids with known viscosities.
Rotational viscometers: Rotational viscometers use the idea that the torque required to turn an object in a fluid is a function of the viscosity of that fluid. They measure the torque required to rotate a disk or bob in a fluid at a known speed.