Ekofisk Formation

{{Short description|Geological formation of Danian (lowermost Paleocene) age}}

{{Infobox rockunit

| name = Ekofisk Formation

| period = Danian

| age = {{fossilrange|Danian}}

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| type = Geological formation

| prilithology = Chalk

| otherlithology = Marl

| unitof = Chalk Group

| subunits =

| underlies = Våle Formation

| overlies = Tor Formation

| thickness = up to {{Convert|150|m|ft|-1}}

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| region = North Sea

| country = Denmark, Netherlands, Norway & United Kingdom

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| namedfor = Ekofisk field

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| location_ts = Well 2/4-5. Norwegian sector

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The Ekofisk Formation is a geological formation of Danian (lowermost Paleocene) age. It forms the uppermost part of the Chalk Group in the North Sea. It is an important reservoir for oil and gas in fields such as Ekofisk. It overlies the Maastrichtian Tor Formation with local evidence of unconformity. It underlies the Våle Formation.{{Cite web |last=NPD |title=Ekofisk Fm |url=https://factpages.npd.no/en/strat/PageView/Litho/Formations/33 |website=Norwegian Petroleum Directorate Fact Pages|access-date=25 August 2022 }}{{Cite web |last=British Geological Survey |title=Ekofisk Formation |url=https://webapps.bgs.ac.uk/lexicon/lexicon.cfm?pub=EKOF |access-date=26 August 2022 |website=The BGS Lexicon of Named Rock Units}}{{Cite web |last=DINOloket |title=Ekofisk Formation |url=https://www.dinoloket.nl/en/stratigraphic-nomenclature/ekofisk-formation |website=Stratigraphic nomenclature|access-date=26 August 2022 }}{{Cite journal |last=Blinkenberg |first=K.H. |last2=Anderskouv |first2=K. |last3=Sheldon |first3=E. |last4=Bjerrum |first4=C.J. |last5=Stemmerik |first5=L. |date=2020 |title=Stratigraphically controlled silicification in Danian chalk and its implications for reservoir properties, southern Danish Central Graben |journal=Marine and Petroleum Geology |volume=115 |doi=10.1016/j.marpetgeo.2019.104134}}