Soil gas measurements of radon, CO2 and hydrocarbon concentrations as indicators of subsurface hydrocarbon accumulation and hydrocarbon seepage

Scientific paper - Original scientific paper

• Author: Marko Cvetković
• Author: Josipa Kapuralić
• Author: Marija Pejić
• Author: Iva Kolenković Močilac
• Author: David Rukavina
• Author: Duje Smirčić
• Author: Ana Kamenski https://orcid.org/0000-0002-1237-1007
• Author: Bojan Matoš
• Author: Marko Špelić https://orcid.org/0000-0003-1010-2505
• Author's institution: Croatian Geological Survey
• Author's institution: University of Zagreb; Faculty of Mining, Geology and Petroleum Engineering; (Department of Geophysical Exploration and Mine Surveying)
• Author's institution: University of Zagreb; Faculty of Mining, Geology and Petroleum Engineering; (Department of Geology and Geological Engineering)
• Author's institution: University of Zagreb; Faculty of Mining, Geology and Petroleum Engineering; (Department of Mineralogy, Petrology and Mineral Resources)
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Geology
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Interdisciplinary Natural Sciences

Abstract (english)

Soil gas measurements of radon (222Rn), CO2, and hydrocarbon concentrations, as well as gamma-ray spectrometry, were conducted at two separate locations to estimate the measurement results for known locations of hydrocarbon accumulations in the subsurface and oil seepage on the surface. The aim of the study was to confirm the applicability of the method for identifying migration pathways (e.g., faults) and to detect possible seepages of hydrocarbons to the surface as well as to investigate possible health issue potential about the soil gas analysis results. Site A investigations were performed with a large number of sampling points to provide sufficient spatial coverage to capture the influence of subsurface lithologic variability as well as the influence of the migration pathway on the measured parameters. For the investigation of site B, sampling points were positioned to reflect the situation between the area above producing hydrocarbon fields and areas with no confirmed accumulation. The results presented show that it is possible to distinguish the near-surface lithology (gamma-ray spectrometry), characterize the migration pathway, and indicate the area of oil seepage at the surface. Areas above the known hydrocarbon accumulations generally have elevated radon concentrations and detectable heavier hydrocarbons with sporadic methane in soil gas, which contrasts with the lower radon levels and lack of detectable heavier hydrocarbons in soil gas in the area with no confirmed hydrocarbon accumulation in the subsurface.

• Keywords (english): radon; carbon dioxide; hydrocarbon exploration; soil gas; Croatia
• Language: english
• Publication type: Scientific paper - Original scientific paper
• Publication status: Published
• Peer review: Peer review - international
• Publication version: Published version
• Journal title: Sustainability
• Numbering: vol. 13, no. 7, 3840
• e-ISSN: 2071-1050
• DOI: https://doi.org/10.3390/su13073840
• URN:NBN: urn:nbn:hr:169:239739
• Publication: 2021-03-31
• Project: Number: UIP-2019-04-3846; Title (croatian): GEOloška karakterizacija podzemlja istočnog dijela Dravske depresije s ciljem procjene Energetskog Potencijala; Title (english): GEOlogical characterization of the Eastern part of the Drava depression subsurface intended for the evaluation of Energy Potentials; Acronym: GEODEP; Leader: Marko Cvetković; Jurisdiction: Croatia; Funding stream: UIP
• Document URL: https://www.mdpi.com/2071-1050/13/7/3840
• Type of resource: Text
• Access conditions: Open access
• Created on: 2021-04-09 07:07:20