The effects of water-rock interactions on the permeability of the Precambrian Basement in  Southern Saskatchewan

Smith, Taylor

The effects of water-rock interactions on the permeability of the Precambrian Basement in Southern Saskatchewan

dc.contributor.advisor	Tutolo, Benjamin
dc.contributor.author	Smith, Taylor
dc.contributor.committeemember	Lauer, Rachel
dc.contributor.committeemember	Shor, Roman
dc.contributor.committeemember	Grasby, Stephen
dc.date	2023-11
dc.date.accessioned	2023-06-22T15:37:06Z
dc.date.available	2023-06-22T15:37:06Z
dc.date.issued	2023-06-14
dc.description.abstract	Geothermal energy has gained significance as a potential low-carbon, renewable energy source. Approximately 70% of the world’s geothermal reservoirs are defined as low temperature (<150°C), with the potential to power agricultural machinery, support direct heating of homes, buildings, and therapeutic facilities, and produce electricity using specialized facilities. The Precambrian basement underlying the Williston Basin in southern Saskatchewan, with a reservoir temperature of ~120°C, represents one such geothermal resource. Well tests and examination of recovered samples suggest that this, and other similar reservoirs globally, present suitable conditions for geothermal energy production. However, geochemically induced permeability alteration in these potentially highly reactive granitoid rocks presents a significant risk to sustained heat production from these low-temperature resources. To assess this risk, and potentially identify mitigation measures, we conducted a geochemical and mineralogical study of samples recovered from this reservoir. Mineral composition and thermal history of both altered and unaltered samples were quantified through a combination of petrographic, Raman Spectroscopy, and Electronic Microprobe analyses, and the resultant values were then utilized to parameterize geochemical simulations of water-rock interactions at relevant conditions. The simulations permitted prediction of mineral volume changes, and hence inferences about porosity and permeability changes, as a result of these interactions. The simulations suggest that mineral volume will increase as a result of water-rock interaction in both unaltered and altered zones of the basement rocks permeability, but that the geothermal alteration of the unaltered, and hence more reactive, rocks would yield mineral volume changes around 30% greater than the altered rock. Applying the porosity-permeability relationship equation developed by Verma and Pruess (1988), the calculated change in permeability indicates the unaltered Precambrian basement rock will experience a greater change in total permeability compared to the altered basement rocks. Additional calculations show that the Verma Pruess’s equation is sensitive to critical porosity and fitting parameter and predicts various scenarios resulting in a range of permeability change from 1x10-13 to 1x10-20 m2. Based on this result, we infer that altered, permeable zones of the Precambrian basement underlying the Williston basin are likely to provide conditions favorable for the sustained, multi-decade heat production that would be required to justify initial capital expenditures, and hence should be targeted over less altered zones. Geothermal heat extraction from permeable, altered zones of warm Precambrian granitoid rocks globally is an understudied but potentially fruitful resource to reliably produce low-carbon, renewable energy as we seek to decarbonize the global economy.
dc.identifier.citation	Smith, T. (2023). The effects of water-rock interactions on the permeability of the Precambrian basement in southern Saskatchewan (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.
dc.identifier.uri	https://hdl.handle.net/1880/116637
dc.identifier.uri	https://dx.doi.org/10.11575/PRISM/41480
dc.language.iso	en
dc.publisher.faculty	Graduate Studies
dc.publisher.institution	University of Calgary
dc.rights	University of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.
dc.subject	Geothermal
dc.subject	Hydrogeology
dc.subject	Water-rock Interactions
dc.subject	Saskatchewan
dc.subject	Geochemistry
dc.subject.classification	Geochemistry
dc.subject.classification	Geology
dc.subject.classification	Hydrology
dc.title	The effects of water-rock interactions on the permeability of the Precambrian Basement in Southern Saskatchewan
dc.type	master thesis
thesis.degree.discipline	Geoscience
thesis.degree.grantor	University of Calgary
thesis.degree.name	Master of Science (MSc)
ucalgary.thesis.accesssetbystudent	I do not require a thesis withhold – my thesis will have open access and can be viewed and downloaded publicly as soon as possible.