Journal Article

Stress dependence of rock fracture permeability: A comprehensive review of laboratory data and implications for hydraulic stimulation

Zhu, Honghu, Hofmann, Hannes, Ji, Yinlin, Zhang, Supeng, He, Zhiqiang, Jing, Xudong, Wang, Qin

2026

Overview

Fracture permeability controls the fluid flow in unconventional geo-energy reservoirs, and achieving an effective and sustainable increase in permeability is a primary objective of hydraulic stimulation treatments. However, the stress dependence of fracture permeability remains insufficiently constrained. In this study, we systematically compiled and re-processed published hydro-mechanical data of tensile, shear, saw-cut, and natural fractures in representative reservoir rocks, including shale, tight sandstone and crystalline rocks, under diverse stress and deformation conditions. We calculated the fracture permeability, synthesized a unified dataset and systematically quantified the permeability variations with Terzaghi effective normal stress using a commonly adopted exponential law characterized by intrinsic permeability ( k 0 ) and normal stress sensitivity ( α ). The synthesized dataset indicates that shale fractures are associated with low k 0 and moderate α , suggesting the potential importance of proppant use for maintaining fracture permeability in shale oil/gas reservoirs; sandstone fractures possess high k 0 and low α , favoring sustainable stimulation effects; and crystalline rock fractures have intermediate k 0 and high α , requiring proppants for maintaining post-stimulation permeability. Slip events are generally accompanied by increases in both k 0 and α , enhancing permeability but making it more sensitive to pressure changes, whereas cyclic fluid pressure changes generally compact fractures and reduce both parameters. Laboratory-scale data suggests that shear stress tends to decrease fracture permeability due to asperity crushing and clogging, while field-scale evidence implies permeability enhancement of critically stressed fractures through brecciation. Overall, this study provides a systematic synthesis of existing data for interpreting stress-dependent fracture permeability, which may inform stimulation strategies designed to enhance and sustain fluid transport in unconventional geo-energy reservoirs.

• Publisher: Springer Nature Singapore,Springer,Springer Nature B.V,SpringerOpen
• Subject: Crystalline rocks / Deformation / Energy / Fluid flow / Fossil Fuels (incl. Carbon Capture) / Fracture permeability / Fractures / Fractures (Geology) / Geotechnical Engineering & Applied Earth Sciences / Hydraulic stimulation / Hydraulics / Mineral Resources / Oil reservoirs / Permeability / Permeability enhancement / Rock fracture permeability / Sandstone / Shales / Shear strength / Shear stress / Stress dependence / Unconventional geo-energy / Velocity