Measurement of Permeability and Verification of Kozeny-Carman Equation Using Statistic Method

Abstract

The permeability of the porous media is a critical parameter that could determine the technical and economical feasibility of gas recovery from natural gas hydrate reservoirs. The developed one-dimensional apparatus could be used to measure the permeability of the porous media with or without hydrate. Stable fluid flow rate and differential pressure could be obtained under certain system pressure and temperature. The densities, the grain size distributions, the volume weighted mean diameters and the specific surface areas of different quartz sands. Based on the Darcy’s Law, the water permeability was measured under stable state. The experimental results indicated that the absolute permeability of quartz sand without hydrate was 52.32, 35.52 and 21.10 Darcies. Some of the parameters in the Kozeny-Carman equation, such as the porosity, the internal pore surface area and the total pore volume were measured directly in the laboratory. The shape factor, which was significantly sensitive to the characteristics of the porous media, was evaluated using the statistic methods. Mathematical calculation steps of the shape factor were introduced, during which there was only one adjustable parameter which represented the roughness of the surface of the porous media. This method could be used to investigate the permeability of the porous media in the presence of natural gas hydrate, which is in solid phase. The measurements of the density, the grain size distribution and the specific surface area of the hydrate-bearing quartz sands should under high pressure and low temperature conditions, which are favorable for stable hydrate existence.