The paper presents the gas permeability of marine sediments in the Shenhu Area of South China Sea. The sediments were obtained at the depth of 1600m below sea level. The solid density and volume weighted mean diameter of the sediments were 2.421 g/cm3 and 6.491 μm, respectively. The gas permeability of the marine sediments was measured by steady state method with confining pressures of 2MPa, 5MPa, 8MPa, 10MPa, 15MPa, 20MPa, 23MPa. The effective gas permeability of the sediments decreased from 2.638 × 10-16 m2 to 0.872 × 10-16 m2 as the confining pressure increased from 2 MPa to 23 MPa. The porosity of the sediments decreased from 41.82 % to 29.54 % as the confining pressure increased from 0 to 23 MPa. The gas permeability of the sediments was determined to be 1.535 × 10-16 m2 with confining pressure of 15 MPa and the porosity of 32.00 %. The longitudinal deformation of the sample was very sensitive to the confining pressure, and the compressibility of the sample in the radial direction was not obvious. The particle size term in the classical Kozeny-Carman equation was revised by a correction factor (N), and the experimental results fitted well with the curves when N value was 2.40. The reference group experiments indicated that the measurement results were reproducible.
Keywords gas permeability; South China Sea; marine sediments; steady state method; Kozeny-Carman