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Experimental and modeling study of fluid pressure‐driven fractures in Darley Dale sandstone
Author(s) -
Vinciguerra Sergio,
Meredith Philip G.,
Hazzard Jim
Publication year - 2004
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2004gl019638
Subject(s) - acoustic emission , geology , fluid pressure , mechanics , fracture (geology) , fluid dynamics , internal pressure , phase (matter) , flow (mathematics) , geotechnical engineering , materials science , physics , composite material , quantum mechanics
We report measurements of acoustic emissions (AE) generated during formation and growth of pressure driven fractures in cylindrical samples of Darley Dale sandstone that were co‐axially pre‐drilled in order to allow an internal pressure to be applied. A set of 3 to 6 fractures initiate at the wall of the internal bore at a fluid pressure around three times that of the confining pressure, but only 3 propagate to the outer wall of the sample. Time and spatial distributions of acoustic emissions show two distinct bursts of activity, associated with initiation and propagation, respectively. A Particle Flow Code (PFC) model has been used to reproduce the mechanics of fracture initiation and the time and spatial distributions of AE. In both the experiments and the model, we observe a distinct phase of accelerating AE activity preceding fracture formation.