Toggle Main Menu Toggle Search

Open Access padlockePrints

Assessing the fugitive emission of CH4 via migration along fault zones – Comparing potential shale gas basins to non-shale basins in the UK

Lookup NU author(s): Sam Almond, Professor Richard DaviesORCiD

Downloads


Licence

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).


Abstract

© 2016 The AuthorsThis study considered whether faults bounding hydrocarbon-bearing basins could be conduits for methane release to the atmosphere. Five basin bounding faults in the UK were considered: two which bounded potential shale gas basins; two faults that bounded coal basins; and one that bounded a basin with no known hydrocarbon deposits. In each basin, two mobile methane surveys were conducted, one along the surface expression of the basin bounding fault and one along a line of similar length but not intersecting the fault. All survey data was corrected for wind direction, the ambient CH4 concentration and the distance to the possible source. The survey design allowed for Analysis of Variance and this showed that there was a significant difference between the fault and control survey lines though a significant flux from the fault was not found in all basins and there was no apparent link to the presence, or absence, of hydrocarbons. As such, shale basins did not have a significantly different CH4 flux to non-shale hydrocarbon basins and non-hydrocarbon basins. These results could have implications for CH4 emissions from faults both in the UK and globally. Including all the corrected fault data, we estimate faults have an emissions factor of 11.5 ± 6.3 t CH4/km/yr, while the most conservative estimate of the flux from faults is 0.7 ± 0.3 t CH4/km/yr. The use of isotopes meant that at least one site of thermogenic flux from a fault could be identified. However, the total length of faults that penetrate through-basins and go from the surface to hydrocarbon reservoirs at depth in the UK is not known; as such, the emissions factor could not be multiplied by an activity level to estimate a total UK CH4 flux.


Publication metadata

Author(s): Boothroyd IM, Almond S, Worrall F, Davies RJ

Publication type: Article

Publication status: Published

Journal: Science of the Total Environment

Year: 2017

Volume: 580

Pages: 412-424

Print publication date: 15/02/2017

Online publication date: 01/12/2016

Acceptance date: 07/09/2016

Date deposited: 11/04/2017

ISSN (print): 0048-9697

ISSN (electronic): 1879-1026

Publisher: Elsevier B.V.

URL: https://doi.org/10.1016/j.scitotenv.2016.09.052

DOI: 10.1016/j.scitotenv.2016.09.052


Altmetrics

Altmetrics provided by Altmetric


Share