The study of water saturation process of dolomite core under atmospheric pressure by MRI method

Abstract

The distribution of the fluid content in the process of water saturation of fine-grained full-sized dolomite core has been measured by magnetic resonance imaging (MRI). Two stages have been allocated in the saturation process. A rapid growth (up to 5 min) of the fluid content in the near-surface core layer (~ 0.5 cm) to the maximum saturation has been observed at the first “hydrodynamic” stage of the process. The hydrodynamic stage of fluid saturation with a void rock space has been considered in the framework of the Darcy filtration model. The pressure gradient in this model has been determined by the difference between the pressure of the fluid formed from the hydrostatic and capillary pressure and the increasing pressure of the compressed gas (air) in the confined pore space. At the second, “diffusion”, stage (from 5 to 320 min), the slow growth of the water content profile has been observed in the central part of the core compared to the hydrodynamic stage. The diffusion stage of saturation has been considered within the model of equilibrium of fluid and gas pressures. The mass transfer of the fluid is carried out at the expense of the fluid content gradient.

Keywords

• water saturation
• porous space
• dolomite core
• magnetic resonance imaging
• diffusion in porous space