Cyclic confining pressure and rock permeability: Mechanical compaction or fines migration.

The apparent rocks permeability, measured under cyclic loading, tends to constantly decrease with each subsequent loading/unloading cycle, the main reason for this, the researchers consider irreversible deformations. However, this understanding is not complete, as attention is not paid to the method of determining the permeability. Under cyclic loading, permeability is measured by fluid flow, which is able to carry colloids and they can clog pore throats and reduce permeability, but this is not taken into account in the study of porous rocks.

The Rehbinder Effect in Testing Saturated Carbonate Geomaterials.

Carbonate geomaterial samples were tested for uniaxial compressive strength and tensile strength under air-dried and distilled-water-wet conditions. When tested for uniaxial compression, samples saturated with distilled water showed 20% lower average strength than that of air-dried samples. In the indirect tensile (Brazilian) test, samples saturated with distilled water showed 25% lower average strength than that of dry samples.