Physics Today, Backscatter, March 2018
James M. Campbell, Deren Ozturk, and Bjørnar Sandnes
Phys. Rev. Applied 8, 064029 – Published 29 December 2017
Gas-driven fracturing underlies both natural and industrial processes, such as volcanic degassing, methane venting, stimulated hydrocarbon extraction, and treatment of contaminated soil. The authors show how in such a complex system the capillary, frictional, and viscous interactions together produce a range of fracture patterns, with cracks separated by a characteristic length that varies based on the conditions. Discovering how material properties and injection rate affect these patterns helps to establish a physics framework for optimizing permeability and assessing risk in gas-driven fracturing of hydrocarbon reservoirs and remediation of polluted soil.
Guillaume Dumazer (UiO) presented at Powders & Grains 2017.
Download paper: “Self-Structuring of Granular material under Capillary Bulldozing“. Guillaume Dumazer, Bjørnar Sandnes, Monem Ayaz, Knut Jørgen Måløy and Eirik Flekkøy. EPJ Web Conf. Vol. 140, 2017.
This movie shows what happens when you inject a gas into a granular suspension at different injection rates. At low rates, “stick slip” bubbles emerge, followed by “temporal intermittency” where periods of continuous motion are interrupted by occasional jamming. Increasing the injection rate further produces a spectacular “coral”-like pattern, and ultimately destabilized viscous fingers appear at high rates.