The characterization of time-dependent brittle rock deformation is fundamental to understanding the long-term evolution and dynamics of reservoir and aquifers. Conventional creep experiments have shown that differential stress exerts a crucial influence on both creep strain rate and time-to-failure in porous sandstone. They have also demonstrated that a critical level of damage needs to be reached before the onset of accelerating tertiary creep. Our experimental data has demonstrated the fundamental characteristics of brittle creep in sandstone, such as sensitivity to temperature, as well as the contribution of variables such as effective pressure (Peff). Data derived from our stress-stepping experiments have been shown to compare favourably with those from conventional creep experiments. Stress-stepping creep experiments have shown that an increase in Peff inhibits the process of stress corrosion. We suggest that the most likely cause is a decrease in water mobility due to a reduction in crack aperture at a higher Peff. The sliding wing crack model of Ashby and Sammis (1990) has been coupled to Charles’s description of subcritical crack growth to explore the behaviour of rocks subjected to constant differential stress in a overall compressive stress state. The model successfully reproduces the qualitative behaviour observed in the experiments.


Article metrics loading...

Loading full text...

Full text loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error