High resolution spatial and temporal evolution of dissolved gases in groundwater during a controlled natural gas release experiment

Simple item page
dc.contributor.authorCahill, Aaron G
dc.contributor.authorParker, Beth L
dc.contributor.authorMayer, Bernhard
dc.contributor.authorMayer, K Ulrich
dc.contributor.authorCherry, John A
dc.date.accessioned2023-03-18T02:49:54Z
dc.date.available2023-03-18T02:49:54Z
dc.date.issued2018-05-01
dc.description.abstractFugitive gas comprised primarily of methane (CH4) with traces of ethane and propane (collectively termed C1-3) may negatively impact shallow groundwater when unintentionally released from oil and natural gas wells. Currently, knowledge of fugitive gas migration, subsurface source identification and oxidation potential in groundwater is limited. To advance understanding, a controlled release experiment was performed at the Borden Research Aquifer, Canada, whereby 51m3 of natural gas was injected into an unconfined sand aquifer over 72days with dissolved gases monitored over 323days. During active gas injection, a dispersed plume of dissolved C1-3 evolved in a depth discrete and spatially complex manner. Evolution of the dissolved gas plume was driven by free-phase gas migration controlled by small-scale sediment layering and anisotropy. Upon cessation of gas injection, C1-3 concentrations increased to the greatest levels observed, particularly at 2 and 6m depths, reaching up to 31.5, 1.5 and 0.1mg/L respectively before stabilizing and persisting. At no time did groundwater become fully saturated with natural gas at the scale of sampling undertaken. Throughout the experiment the isotopic composition of injected methane (δ13C of -42.2‰) and the wetness parameter (i.e. the ratio of C1 to C2+) constituted excellent tracers for the presence of fugitive gas at concentrations >2mg/L. At discrete times C1-3 concentrations varied by up to 4 orders of magnitude over 8m of aquifer thickness (e.g. from <0.01 to 30mg/L for CH4), while some groundwater samples lacked evidence of fugitive gas, despite being within 10m of the injection zone. Meanwhile, carbon isotope ratios of dissolved CH4 showed no evidence of oxidation. Our results show that while impacts to aquifers from a fugitive gas event are readily detectable at discrete depths, they are spatially and temporally variable and dissolved methane has propensity to persist.en_US
dc.identifier.citationCahill, A. G., Parker, B. L., Mayer, B., Mayer, K. U., & Cherry, J. A. (2018). High resolution spatial and temporal evolution of dissolved gases in groundwater during a controlled natural gas release experiment. Science of The Total Environment, 622–623, 1178–1192. https://doi.org/10.1016/j.scitotenv.2017.12.049en_US
dc.identifier.doihttp://dx.doi.org/10.1016/j.scitotenv.2017.12.049en_US
dc.identifier.urihttp://hdl.handle.net/1880/115933
dc.identifier.urihttps://doi.org/10.11575/PRISM/46115
dc.language.isoengen_US
dc.publisherElsevieren_US
dc.publisher.departmentGeoscienceen_US
dc.publisher.facultyScienceen_US
dc.publisher.hasversionacceptedVersionen_US
dc.publisher.institutionUniversity of Calgaryen_US
dc.publisher.policyhttps://www.elsevier.com/journals/science-of-the-total-environment/0048-9697/open-access-optionsen_US
dc.rightsUnless otherwise indicated, this material is protected by copyright and has been made available with authorization from the copyright owner. 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.en_US
dc.titleHigh resolution spatial and temporal evolution of dissolved gases in groundwater during a controlled natural gas release experimenten_US
dc.typejournal articleen_US
ucalgary.item.requestcopytrueen_US
ucalgary.scholar.levelFacultyen_US
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
Cahill et al 2017 STOTEN.pdf
Size:
2.59 MB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.92 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Science Research & Publications