New analysis utilizing drilling samples factors to a widespread Miocene-age petroleum system within the jap Nordic Seas that’s much like prolific producing basins offshore West and Central Africa.
The examine printed this week on the Marine and Petroleum Geology journal analyzed outcomes from the Ocean Drilling Program at Web site 909 within the central Fram Strait and Web site 985 within the Iceland Sea; Worldwide Ocean Discovery Program Expedition 396 at Web site U1572 within the Vøring Plateau; exploration wells 6608/10-1 within the Mid-Norwegian margin; and exploration nicely 7316/5-1 within the southwestern Barents Sea. The work was authored by researchers in Norway, together with from the nation’s regulator for upstream oil and gasoline actions.
Boreholes and oil seeps confirmed mature Miocene rocks producing hydrocarbons beneath a kilometer-thick Plio-Pleistocene cowl within the southwestern Barents Sea, based on the examine.
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Biomarkers present in oil seeps and borehole sediments from the websites share comparable traits with these of Niger Delta crude, which come from rocks containing combined marine and terrestrial fossils, it mentioned.
“Probably the most thrilling outcomes is that the research doc a younger supply rock from what was once a large-scale deltaic sedimentary surroundings in massive elements of the Norwegian Sea”, Rune Mattingsdal, a co-author from the Norwegian Offshore Directorate (NOD), was quoted as saying in a web based assertion by the regulator. “The sedimentary circumstances can finest be in contrast with the circumstances within the Niger and Congo deltas off the coast of West Africa”.
The NOD mentioned the examine exhibits potential for unexplored areas within the Norwegian Sea which have already been awarded below Norway’s Awards in Pre-Outlined Areas.
“The organic-rich sediments from ODP/IODP Holes 909C, 985A and U1572B include sturdy terrestrial enter, evidenced by the presence of angiosperm-derived biomarkers reminiscent of oleanane and its precursor, olean-12-ene”, the examine mentioned. “These compounds, together with the sterane, hopane and diasterane distributions, reveal a transparent genetic hyperlink between the oils from the Molloy and Prins Karls Forland oil seeps offshore western Svalbard and the Miocene supply rocks within the studied boreholes.
“The presence of those biomarkers, together with age-diagnostic indices just like the Nordiacholestane Ratio and the oleanane index, confirms that the oil seepage is sourced from Tertiary, deltaic supply rocks wealthy in sort III kerogen. These findings align with tectonic and sedimentological information indicating widespread delta formation through the Early to Center Miocene, attributable to regional uplift occasions in areas reminiscent of East Greenland, the Barents Sea and central Norway. These deltas equipped substantial terrestrial natural matter right into a restricted marine basin, producing splendid circumstances for supply rock deposition below diversified redox circumstances.
“The conceptual analogies drawn with the Niger Delta and Congo fan methods are notably instructive. In all three instances, deep marine sediments enriched with terrestrial natural materials – delivered by river methods and deltaic outflows – served as environment friendly petroleum supply rocks. The Miocene Nordic Seas system resembles this mannequin, with excessive TOC values, angiosperm-derived biomarkers and indicators of oil technology in each floor seeps and deep subsurface sediments.
“Basin modeling on the margin of the SW Barents Sea, utilizing seismic traces and exploration nicely 7316/5-1, confirms the maturity of Miocene supply rocks buried below kilometer-thick Plio-Pleistocene glacial sediments. The thermal modelling at a Pseudo Nicely alongside the seismic line signifies that giant elements of this supply rock are at the moment inside the principle oil window, having been buried deep sufficient to achieve hydrocarbon-generating temperatures. The detection of olean-12-ene in immature sections additional upslope in the direction of the shelf edge (nicely 7316/5-1) corroborates the terrestrial origin and early maturity stage of this supply rock.
“Moreover, the corresponding biomarker composition of oils from seeps and boreholes all through the area supplies sturdy proof of a coherent petroleum system. The spatial distribution – from the Arctic-Atlantic Gateway (Fram Strait) to the SW Barents Sea and Mid-Norwegian margin – suggests a geographically intensive Miocene supply rock interval. The affirmation of such a system not solely advances geological understanding but additionally highlights untapped petroleum exploration potential in underexplored areas just like the SW Barents Sea.
“Whereas additional drilling and sampling are wanted to validate the financial viability of this technique, the presence of biomarkers reminiscent of oleanane and olean-12-ene throughout a wide range of maturity ranges and settings demonstrates a constant supply enter and a dynamic depositional surroundings.
“Collectively, these findings point out that the Miocene supply rocks of the jap Nordic Seas symbolize a major, deltaic-driven petroleum system analogous to a number of the world’s most efficient offshore basins.
“Potential play varieties embrace stratigraphic traps in slope and basin flooring followers, and structural traps associated to Miocene deltaic loading and Plio-Pleistocene glacial overburden.
“Nonetheless, key exploration dangers stay, notably when it comes to reservoir high quality, seal integrity and migration pathways inside glacially modified margins”.
To contact the writer, e-mail jov.onsat@rigzone.com
