Geophysical Properties of Hydrate-Bearing Silty-Clayey Sediments with Different Compaction Patterns

Laboratory studies on hydrate electrical resistivity properties considering different pore conditions provide significant insights for hydrate exploration and development. The coupled effects of pressure and a gas–water system on the resistivity properties of hydrate-bearing silty-clayey sediments (HBSCSs) within intricate seafloor geological settings remain ambiguous. In this study, electrical resistivity tests were conducted on HBSCSs prepared by two representative compaction patterns under triaxial conditions, accounting for the effects of hydrate saturation and pressure conditions. It is concluded that silty-clayey sediments in both compaction patterns exhibit a consistent trend of resistivity variation corresponding to experimental procedures, and the magnitude of these variations is primarily influenced by changes in pressure conditions and pore medium. The resistivity of unconsolidated silty-clayey sediments reaches approximately 1200 Ω·m with 20% hydrate saturation, while the electrical conductivity of HBSCSs could be completely blocked at a 40% hydrate saturation level. Increasing pressure raises water saturation and consequently reduces resistivity, and more pores were retained during consolidation of HBSCSs due to hydrate resisting deformation, resulting in lower resistivity when hydrate forms in consolidated sediment than in unconsolidated sediment at the same pressure level. This study is expected to provide basic data and theoretical support for the electrical resistivity properties of hydrate silty-clayey reservoirs.