Abstract: A system for characterizing rheological properties of granular material. A cylindrical measurement cup containing granular material is subject to a uniform vibration induced by a vibration exciter at a user-determined frequency. At the same time, a rotation or an oscillation of a rotating vane tool is performed within the powder and a response measured. Baffles are affixed to the inner wall of the measurement cup to prevent slippage of the granular material during measurement. An energy imparted to the system from the vibration exciter can be measured by an accelerometer coupled to the measurement cup. When sufficient vibrational energy is supplied to the system, a powder contained therein achieves a particle “temperature” sufficient such that the powder behaves as an ergodic system.

Abstract: A system for characterizing rheological properties of granular material. A cylindrical measurement cup containing granular material is subject to a uniform vibration induced by a vibration exciter at a user-determined frequency. At the same time, a rotation or an oscillation of a rotating vane tool is performed within the powder and a response measured. Baffles are affixed to the inner wall of the measurement cup to prevent slippage of the granular material during measurement. An energy imparted to the system from the vibration exciter can be measured by an accelerometer coupled to the measurement cup. When sufficient vibrational energy is supplied to the system, a powder contained therein achieves a particle “temperature” sufficient such that the powder behaves as an ergodic system.

Abstract: The present invention relates to a process for controlling the permeability of the walls of the geologic formations drilled. The circulating drilling fluid includes a determined amount of gellan used as a filtrate reducer.In the process, the viscosity of the fluid is mainly controlled by polymers, such as xanthan, scleroglucan or wellan.The invention further relates to a drilling fluid including gellan.