title: Evolution of a fracture network in an elastic medium with internal fluid generation and expulsion.
abstract: A simple and reproducible analog experiment was used to simulate fracture formation in a low-permeability elastic solid during internal fluid/gas production, with the objective of developing a better understanding of the mechanisms that control the dynamics of fracturing, fracture opening and closing, and fluid transport. In the experiment, nucleation, propagation, and coalescence of fractures within an elastic gelatin matrix, confined in a Hele-Shaw cell, occurred due to CO_{2} production via fermentation of sugar, and it was monitored by optical means. We first quantified how a fracture network develops, and then how intermittent fluid transport is controlled by the dynamics of opening and closing of fractures. The gas escape dynamics exhibited three characteristic behaviors: (1) Quasiperiodic release of gas with a characteristic frequency that depends on the gas production rate but not on the system size. (2) A 1/f power spectrum for the fluctuations in the total open fracture area over an intermediate range of frequencies (f), which we attribute to collective effects caused by interaction between fractures in the drainage network. (3) A 1/f^{2} power spectrum was observed at high frequencies, which can be explained by the characteristic behavior of single fractures.
authors.affiliation: Physics of Geological Processes, University of Oslo, Norway.
authors.forename: Maya
authors.initials: M
authors.lastname: Kobchenko
authors.affiliation: Physics of Geological Processes, University of Oslo, Norway.
authors.forename: Andreas
authors.initials: A
authors.lastname: Hafver
authors.affiliation: Physics of Geological Processes, University of Oslo, Norway and IRIS AS, P.O. Box 8046, N-4068 Stavanger, Norway.
authors.forename: Espen
authors.initials: E
authors.lastname: Jettestuen
authors.affiliation: Physics of Geological Processes, University of Oslo, Norway and Université de Grenoble Alpes, ISTerre, BP 53, F-38041, Grenoble, France and CNRS, ISTerre, BP 53, F-38041, Grenoble, France.
authors.forename: François
authors.initials: F
authors.lastname: Renard
authors.affiliation: Physics of Geological Processes, University of Oslo, Norway.
authors.forename: Olivier
authors.initials: O
authors.lastname: Galland
authors.affiliation: Physics of Geological Processes, University of Oslo, Norway.
authors.forename: Bjørn
authors.initials: B
authors.lastname: Jamtveit
authors.affiliation: Physics of Geological Processes, University of Oslo, Norway and Department of Physics, Temple University, Philadelphia, Pennsylvania, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Meakin
authors.affiliation: Physics of Geological Processes, University of Oslo, Norway.
authors.forename: Dag Kristian
authors.initials: DK
authors.lastname: Dysthe