title: Ultrasonic compaction of granular geological materials.
abstract: It has been shown that the compaction of granular materials for applications such as pharmaceutical tableting and plastic moulding can be enhanced by ultrasonic vibration of the compaction die. Ultrasonic vibrations can reduce the compaction pressure and increase particle fusion, leading to higher strength products. In this paper, the potential benefits of ultrasonics in the compaction of geological granular materials in downhole applications are explored, to gain insight into the effects of ultrasonic vibrations on compaction of different materials commonly encountered in sub-sea drilling. Ultrasonic vibrations are applied, using a resonant 20kHz compactor, to the compaction of loose sand and drill waste cuttings derived from oolitic limestone, clean quartz sandstone, and slate-phyllite. For each material, a higher strain for a given compaction pressure was achieved, with higher sample density compared to that in the case of an absence of ultrasonics. The relationships between the operational parameters of ultrasonic vibration amplitude and true strain rate are explored and shown to be dependent on the physical characteristics of the compacting materials.
authors.affiliation: School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Feeney
authors.affiliation: Badger Explorer ASA, Stavanger 4068, Norway.
authors.forename: Sakalima
authors.initials: S
authors.lastname: Sikaneta
authors.affiliation: School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: Patrick
authors.initials: P
authors.lastname: Harkness
authors.affiliation: School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK. Electronic address: Margaret.Lucas@glasgow.ac.uk.
authors.forename: Margaret
authors.initials: M
authors.lastname: Lucas
keywords: Granular materials; Sub-sea exploration; Ultrasonic compaction