ERA

Download the full-sized PDF of Isotope Geochemistry of Natural Gas from the Horn River Basin: Understanding Gas Origin, Storage and Transport in an Unconventional Shale PlayDownload the full-sized PDF

Analytics

Share

Permanent link (DOI): https://doi.org/10.7939/R3Q815012

Download

Export to: EndNote  |  Zotero  |  Mendeley

Communities

This file is in the following communities:

Graduate Studies and Research, Faculty of

Collections

This file is in the following collections:

Theses and Dissertations

Isotope Geochemistry of Natural Gas from the Horn River Basin: Understanding Gas Origin, Storage and Transport in an Unconventional Shale Play Open Access

Descriptions

Other title
Subject/Keyword
unconventional gas
thermogenic gas
non-conventional gas
geochemistry
stable isotope
Horn River Basin
shale gas
Type of item
Thesis
Degree grantor
University of Alberta
Author or creator
Norville, Giselle A
Supervisor and department
Muehlenbachs, Karlis (Earth and Atmospheric Sciences)
Examining committee member and department
Gingras, Murray (Earth and Atmospheric Sciences)
Rostron, Ben (Earth and Atmospheric Sciences)
Zonneveld, John - Paul (Earth and Atmospheric Sciences)
Mayer, Bernhard (Geoscience)
Department
Department of Earth and Atmospheric Sciences
Specialization

Date accepted
2014-06-25T11:28:05Z
Graduation date
2014-11
Degree
Doctor of Philosophy
Degree level
Doctoral
Abstract
Devonian shales of the Horn River Basin, northeast British Columbia are recognized key targets for unconventional shale gas production in Canada. Recent studies show gas isotope geochemistry in several unconventional shale plays worldwide differ from conventional hydrocarbon reservoirs and carbon isotope reversal between hydrocarbon gas components is a common phenomenon. Geochemical properties of natural gases hold clues to origin, storage and transport within the shale and may assist in elucidation of the shale gas system; however limited published work exists on stable isotope geochemistry of Horn River Basin shale gases. Over four hundred mud gas and production gas samples were obtained from Phanerozoic formations in the Dilly Creek area of the basin and chemical and stable isotope compositions were measured. Carbon isotope depth profiles of Horn River Basin gases (methane, ethane and propane) from surface depth to the target formation provide a geochemical template applicable for use in environmental remediation. Isotope signatures (δ¹³C methane, δ¹³C ethane and δ¹³C propane) of surface casing vent gas and soil gas at six leaking well sites in the basin were matched to isotope depth profiles which allow identification of formations from which gas leaks occurred. Carbon isotope lateral profiles map the subsurface variation within shale gas target formations and serve as a proxy for flow connectivity within the shale. Inter- and intra-formational variations in δ¹³C methane values of Horn River Group gases are observed and carbon isotope data purports greater connectivity in the Muskwa Formation than in the Otter Park Formation. Time series data show stable isotope compositional changes during shale gas production and fluctuations in δ¹³C values of produced Muskwa, Otter Park and Evie gases occur with unique trends for each well. In the early stage of production Horn River Group gases generally show more negative δ¹³C methane values, while increases in δ¹³C methane values are observed in after periods of well ‘shut in’ and overall δ¹³C methane values ranged from approximately -38‰ to -28‰. Horn River Group gas isotope signatures indicate gases are dry, mature and thermogenic in origin and several shale gas samples exhibit isotopically reversed gas signatures. Few cases of carbon isotope reversal were observed in mud gases while most produced gases showed partial isotope reversal among gas components or full isotope reversals where δ¹³C methane > δ¹³C ethane > δ¹³C propane. It is plausible that carbon isotope fractionation occurs during shale gas production as hydrocarbon molecules traverse tortuous pathways within the complex shale fabric which alters the carbon isotope signature of produced gases. Spatial and temporal stable isotope variations occur in Devonian shale gases in the Horn River Basin and this should be taken into consideration during interpretation of isotope data obtained from unconventional shale gas reservoirs.
Language
English
DOI
doi:10.7939/R3Q815012
Rights
Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.
Citation for previous publication

File Details

Date Uploaded
Date Modified
2015-01-08T08:02:55.825+00:00
Audit Status
Audits have not yet been run on this file.
Characterization
File format: pdf (PDF/A)
Mime type: application/pdf
File size: 7136084
Last modified: 2015:10:22 06:25:11-06:00
Filename: Norville_Giselle_A_201406_PhD.pdf
Original checksum: 88f2e7ab6a66886cb58fbdf1dfaedc5b
Activity of users you follow
User Activity Date