Stress Sensitivity and Permeability in Porous Media

Stress sensitivity refers to the tendency of a porous material’s permeability to change in response to variations in effective stress, pore pressure or mechanical loading. In most geological formations, pore spaces and fractures comprise the fluid pathways that govern flow rates, storage and transport properties. Under increased effective stress the pore network may compact, fracture apertures close or microcracks evolve, all of which can lead to marked reductions in permeability. Conversely, unloading may induce partial or hysteretic recovery depending on irreversible deformation or cementation. Understanding these processes is critical for optimising hydrocarbon and geothermal production, enhancing carbon sequestration, managing groundwater resources and predicting aquifer behaviour under anthropogenic loads. Recent advances in imaging, laboratory testing and numerical modelling have elucidated the coupling between mechanical deformation and fluid flow at scales ranging from nanometres to metres, revealing the roles of pore geometry, mineral composition and microstructure on stress–permeability relations.

Research from Nature Portfolio

Recent studies have applied high-resolution micro-CT scanning during in situ stress-sensitivity tests to differentiate types of permeability loss in deep clastic reservoirs. By correlating pore-fracture morphology with irreversible damage metrics, researchers have classified stress-sensitivity behaviour into distinct regimes of rapid permeability change with weak damage versus moderate change with strong damage, attributing these to the relative abundance of micro-fractures or micropores. Another investigation combined laboratory gas-permeability experiments on shale with a modified Klinkenberg framework to integrate competing effects of gas slippage and effective stress. This work established a pressure threshold at which slippage dominance gives way to stress control, and proposed a conceptual model linking pore-scale geometry, water content and mechanical loading to apparent permeability variations in nanoporous media.

Stress Sensitivity and Permeability in Porous Media publication trend

The graph below shows the total number of articles in stress sensitivity and permeability in porous media across all publications each year (not limited to Nature Index journals).

Technical terms

Effective stress: The difference between confining stress and pore pressure that drives deformation of the solid matrix.

Permeability: A measure of a porous medium’s ability to transmit fluids, often expressed in darcy or millidarcy units.

Porosity: The fraction of the total volume occupied by voids or pores, determining storage capacity and influencing flow.

Fracture aperture: The average opening width between fracture faces, a key determinant of fracture permeability.

Klinkenberg effect: The increase in measured gas permeability at low pressures due to gas slippage along pore walls.

Micro-CT scanning: A non-destructive imaging technique that provides three-dimensional visualisation of internal structures at micron resolution.

References

1. Differential characterization of stress sensitivity and its main control mechanism in deep pore-fracture clastic reservoirs. Scientific Reports (2021).
2. Experimental investigation on the coupled effect of effective stress and gas slippage on the permeability of shale. Scientific Reports (2017).
3. Stress sensitivity of porosity and permeability under varying hydrostatic stress conditions for different carbonate rock types of the geothermal Malm reservoir in Southern Germany. Geothermal Energy (2021).
4. Research on Stress Sensitivity of Fractured Carbonate Reservoirs Based on CT Technology. Energies (2017).
5. Colloid Migration as a Reason for Porous Sandstone Permeability Degradation during Coreflooding. Energies (2022).