Widespread natural methane and oil leakage from sub-marine Arctic reservoirs

Serov, Pavel; Mattingsdal, Rune; Winsborrow, Monica; Patton, Henry; Andreassen, Karin

doi:10.21203/rs.3.rs-1225012/v1

Cited by 5 publications

(9 citation statements)

References 42 publications

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“…Glacial erosion during this period contributed to releasing oil from shallow depths of the hydrocarbon reserves and also resulted in release of gas hydrates (Kishankov et al, 2022). Erosion and uncapping of these hydrocarbon reservoirs by glacial action have resulted in persistent gas release and oil slick spots (Serov et al, 2023). It is therefore likely that changes to sedimentary basins could have mobilised oils and gases in other glaciated areas of hydrocarbon reserves around the world, both onshore and offshore.…”

Section: Discussionmentioning

confidence: 99%

Oil sands in glacial till as a driver of fast flow and instability in the former Laurentide Ice Sheet: Alberta, Canada

McCerery,

Woodward,

Winter

et al. 2023

Earth Surf Processes Landf

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Reconstructions of the southwestern Laurentide Ice Sheet (LIS) from geomorphology have revealed complex cross‐cutting ice streams, indicative of surging and flow switching. This flow pattern and behaviour is distinct from the rest of the ice sheet where ice streams flowed radially to the ice sheet margin. Many ice streams in the southwestern sector originate around the Alberta Oil Sands (AOS). Previous reports have detected oil sands material in surficial and glacial sediments south of the AOS, demonstrating potential glacial mobilisation of the oil sands. In this study, we use geochemical fingerprinting to systematically investigate surficial sediments from the former Central Alberta Ice Stream (CAIS) flow track. We compare the geochemical signatures of 82 sediments from within and outside the CAIS limits with those of the AOS (from mines and natural exposures), using gas chromatography–mass spectrometry oil–oil correlation techniques. Our results provide geochemical evidence of glacial erosion and long‐distance mobilisation of AOS producing contamination signatures in sediments throughout the CAIS flow track. The strength of the AOS signature is particularly strong in sediments along the terminating margins, to the east of Calgary and in the Cooking Lake area to the southeast of Edmonton. These results inform theoretical models of enhanced slipperiness, inspired by slippery liquid infused porous surfaces (SLIPS), whereby oil lubrication of the basal sediment influences the degree of sliding and basal deformation in the ice stream. We hypothesise that naturally occurring hydrocarbons at the basal interface exerted control on the location of the onset zone of the CAIS and surrounding ice streams in Alberta. The enhanced slipperiness caused by oil contamination may also explain ice streaming and surging in other ice sheets, such as the Barents Sea Ice Sheet, where hydrocarbons are known to have been driven to the sedimentary interface during glaciation.

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Section: Discussionmentioning

confidence: 99%

Oil sands in glacial till as a driver of fast flow and instability in the former Laurentide Ice Sheet: Alberta, Canada

McCerery,

Woodward,

Winter

et al. 2023

Earth Surf Processes Landf

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“…The raw multibean echosubnder data for seafloor mapping and gas flare detection in the water column acquired by CAGE is available at https://dataverse.no/dataset.xhtml?persistentId=doi:10.18710/ I3L0BQ 82 . The gas flare location data and oil slick emission point location data generated in this study are provided in the Source Data file.…”

Section: Data Availabilitymentioning

confidence: 99%

Widespread natural methane and oil leakage from sub-marine Arctic reservoirs

Serov

Mattingsdal²,

Winsborrow

et al. 2023

Nat Commun

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Parceling the anthropogenic and natural (geological) sources of fossil methane in the atmosphere remains problematic due to a lack of distinctive chemical markers for their discrimination. In this light, understanding the distribution and contribution of potential geological methane sources is important. Here we present empirical observations of hitherto undocumented, widespread and extensive methane and oil release from geological reservoirs to the Arctic Ocean. Methane fluxes from >7000 seeps significantly deplete in seawater, but nevertheless reach the sea surface and may transfer to the air. Oil slick emission spots and gas ebullition are persistent across multi-year observations and correlate to formerly glaciated geological structures, which have experienced km-scale glacial erosion that has left hydrocarbon reservoirs partially uncapped since the last deglaciation ~15,000 years ago. Such persistent, geologically controlled, natural hydrocarbon release may be characteristic of formerly glaciated hydrocarbon-bearing basins which are common across polar continental shelves, and could represent an underestimated source of natural fossil methane within the global carbon cycle.

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“…At high latitudes, waxing and waning of glaciers have the most important direct and indirect effect on seepage. Most of the studies from the Norwegian offshore regions link fluid flow anomalies to glacial loading and unloading cycles (Chand et al, 2008;Chand et al, 2012;Crémière et al, 2016a;Portnov et al, 2016;Winsborrow et al, 2016;Andreassen et al, 2017;Serov et al, 2023) or to sudden sediment loading resulting from glacial retreat melt water inflows and associated sediment discharges during glacial retreat (Hustoft et al, 2009;Karstens et al, 2018). Moreover, the glacial cycles create or expand a hydrate stable zone in sediments during loading, holding a reservoir of gas and hydrates.…”

Section: Introductionmentioning

confidence: 99%

Fluid flow at the Loppa High results from the seabed laboratory and test site

Chand,

Brunstad,

Lepland

et al. 2024

Front. Earth Sci.

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The Loppa High is a subsurface structural high located in SW Barents Sea flanked by regional fault complexes where many hydrocarbon discoveries have been made along its peripheries during recent years. Since the petroleum exploration started in the late 1970’s, extensive studies have been undertaken giving a good understanding of the subsurface stratigraphy and the presence and maturation of hydrocarbon sources, fluid migration processes into hydrocarbon traps and seabed seeps. Many shallow gas anomalies are observed in this region due to fluid migration from the deeper reservoirs. Taking advantage of modern echo sounder and sonar technology, a more precise mapping of shallow subsurface became possible as well as detection of seafloor seeps to be inspected and sampled by advanced ROV technology. Presence of thermogenic hydrocarbons in seeps would indicate remobilisation from reservoirs in the subsurface that remained after the Late Paleogene/Neogene tectonism and the Pleistocene glacial rebound. Results of multibeam echosounder mapping of selected areas have been used to select seep sites for detailed investigation using ROV’s, and HUGIN AUV equipped with synthetic aperture sonar (HISAS), methane sniffers and optical cameras. This has aided the selection of optimal sampling sites and the collection of a large amount of sample material including seeping fluids, carbonate crusts and sediments which has been used for geochemical characterization and geochronology. Here, we present the evidence of the hydrocarbon migration and seepage from reservoirs mainly of deep thermogenic origin and altered by shallow storage during and after glaciation. The thermogenic signature of the seeping fluids indicates the long term and large-scale supply of methane to the global methane budget also from similar areas of potential natural leakage from the subsurface to the water column.

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Widespread natural methane and oil leakage from sub-marine Arctic reservoirs

Cited by 5 publications

References 42 publications

Oil sands in glacial till as a driver of fast flow and instability in the former Laurentide Ice Sheet: Alberta, Canada

Oil sands in glacial till as a driver of fast flow and instability in the former Laurentide Ice Sheet: Alberta, Canada

Widespread natural methane and oil leakage from sub-marine Arctic reservoirs

Fluid flow at the Loppa High results from the seabed laboratory and test site

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