Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/117260
Type: Theses
Title: Magnetotelluric monitoring of unconventional resources
Author: Rees, Nigel
Issue Date: 2016
School/Discipline: School of Physical Sciences
Abstract: Extraction of unconventional gas involves the movement of fluids at depth. In the case of shale gas, hydraulic fracturing is performed, where fluids are injected into sequences at high pressures resulting in permeable pathways for the trapped gas to escape. Coal seam gas (CSG) extraction involves a process termed depressurisation, where large volumes of groundwater are extracted from coal measures causing a pressure reduction that allows trapped gas to desorb from the coal seams. One of the key questions the industry sector is facing is whether it can effectively monitor movement of fluids and changes in Earth as these unconventional energy resources are being developed. We present two MT monitoring surveys of unconventional energy resource development. The first survey involves an industrial field study conducted in Queensland, Australia, where MT responses indicated the orientation of fluid flow resulting from depressurisation, which can be mapped and directly attributed to spatial and temporal variations in permeability. The second survey involves monitoring deep hydraulic fracturing of a shale gas reservoir in the Cooper Basin, Australia. MT observations indicated increases in bulk conductivity of 20 – 40% in both the temporal and spatial domain, with these changes caused by a combination of both injected fluid permeability and an increase in wider-scale in-situ permeability. Finally the telluric sounding method is introduced as a potential tool for monitoring hydraulic fracturing at depth. The advantage of this method is that it is relatively easy to measure electric fields with many dipoles and multi-channel systems and therefore electric field arrays could be deployed and left out for continuous monitoring. Additionally, electric field transfer functions are essentially the identity matrix for a 1D Earth no matter what the vertical structure is and therefore monitoring involves plotting deviations relative to the identity matrix.
Advisor: Heinson, Graham
Thiel, Stephan
Dissertation Note: Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Physical Sciences, 2016.
Provenance: This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at: http://www.adelaide.edu.au/legals
Appears in Collections:Research Theses

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