4. The Norwegian North Sea Eva K. Halland (Project Leader), Ine Tørneng Gjeldvik, Wenche Tjelta Johansen, Christian Magnus, Ida Margrete Meling, Stig Pedersen, Fridtjof Riis, Terje Solbakk, Inge Tappel 29 4.1 Geology of the North Sea Central Norwegian- Southern Horda Tampen Spur Møre Group System Series Stage North sea Danish Basin Viking Graben Platform Holo Basin U Calabria Plei QUATERNARY Gela Pia 62° Nordland Plio Zan Utsira Mess - Mio Skade NEOGENE Aquit Chat Vade Olig Rup Grid Grid Pria - Hordaland Frigg Balder Eoc Ypres Forties Sele Fiskebank Sele Hermod Hermod Hermod Sele Tampen Spur Than - Andrew Lista Lista Heimdal Heimdal Lista land Maureen Våle Våle Roga- Pal PALAEOGENE Dan Ekosk Ekosk Ekosk Ty Ty Våle Sogn GrabenHorda Maast Tor Tor Tor Jorsalfare Jorsalfare Hardråde Basin Camp Kyrre Platform Hod Kyrre Kyrre U Sant Hod Hod East ShetlandEast Coni Tryggvason Tryggvason Tryggvason Shetland Blodøks Blodøks Blodøks Tur Blodøks High Utsira Blodøks Svarte Cen Hidra Hidra Svarte Svarte Bergen Alb Rødby Rødby Rødby Mime Rødby Rødby Apt Sola Sola Sola Ran Sola Sola Sola Barr Mime Mime Oslo CRETACEOUS L Tuxen Tuxen Haut Åsgard Platform Åsgard Åsgard Åsgard Åsgard Mime Cromer Knoll Cromer Valang East ShetlandEast Stord Berr Mandal Sauda Draupne Basin Tith Farsund Flekkeord Draupne Eldsk Tau Brae Draupne U Kimm Ula Sogneord Oxf Haugesund Egersund Boknord Heather Heather Viking/Tyne/ Heather Call Sandnes Hugin Fensord Viking Graben Tarbert Krossord . Vestland Bath Øygarden Fault complex Øygarden Fault M Ness Ness Bajoc Bryne Fm Brent/ Fladen Bryne Fm Sleipner Fm Etive Aalen Oseberg JURASSIC Toarc Drake Drake Fjerritslev Cook Cook Stavanger Plienc Burton Utsira Dunlin L Sinem Nansen Amundsen Hett Johansen Gassum Eiriksson High Stat. ? Grp. Rhæt Gassum ? Raude Mors U Nor Skagerrak Lunde Lunde Lunde Carn Alke Alke Alke Alke Sele Jylland Stavanger Ladin Lomvi Lomvi Hegre Lomvi Åsta Graben M Anis Skagerrak TRIASSIC Lolland Teist Teist Teist High Platform Olenek Bacton L Induan Smith Bank Smith Bank Smith Bank Smith Bank Sørvestlandet High Zechstein Zechstein Lopin- Changhsi - Upper Rotliegend 2 Upper Rotliegend 2 Central Graben gian Egersund equ Wuchi Zechstein Guada- Capitan - Basin lupian Roadian Farsund Basin Kung Artin equ Upper Rotliegend 1 Fjerritslev Fault complex PERMIAN Sakm Rotiegend Cisurlian Assel ? ? Gzel ? Norwegian-Danish Basin Kasim 57° Moscov vanian ? Pennsyl- Bash Serpuk Vise ipian CARBONIFEROUS Mississ- Tour Calcareous shales, limestone and marl stringers Uplifted/eroded area Marginal evaporite deposits, sabkha Clastic continental deposits, mainly sandstone Coastal, deltaic and ood-plain deposits Clastic continental deposits, mainly shale and siltstone Marine deposits, mainly sandstone Salt (halite) Shallow-marine deposits, glauconitic Shallow-marine carbonate deposits Shallow-marine deposits, mainly shale Deep-marine carbonate deposits Deep-marine deposits, mainly shale Volcanic deposits Coal Volcanic tu Ice rafted detritus (IRD) Lithostratigraphic chart of the North Sea (NPD) CO2STORAGEATLAS NORWEGIAN CONTINENTAL SHELF 30 4.1 Geology of the North Sea Age Formations & Groups Evaluated Aquifers 3 Pliocene Piacenzian Zanclean First First First First First First 6 Messinian Utsira Fm. horses whales monkeys apes hominids modern 9 Tortonian humans 11 Miocene Serravallian Ve Mb. Utsira and Skade Formations 13 Langhian 15 Burdigalian 17 Neogene Skade Fm. 19 Aquitanian 22 Chattian 24 26 Oligocene Palaeocene Eocene Oligocene Miocene Pliocene 28 Rupelian 30 33 Priabonian 65.5 56 34 23 5 1.8 35 Bartonian Grid Fm. 37 million years 39 42 Eocene Lutetian First dinosaurs Last 44 First land plants First mammals dinosaurs 46 48 Ypresian First insects Paleogene Frigg Fm. 50 Frigg Field Abandoned Gas Field First tetrapods First 53 Balder Fm. Thanetian flowering 55 Fiskebank Fm. Fiskebank Fm. First First reptiles First Selandian shellfish birds plants 57 Paleocene First First mammal- 59 Danian & corals like reptiles Holocene / Pleistocene 62 fish 64 Maastrichtian 66 Tor Fm. 68 70 73 Ordo- Carboni- Paleo- Neo- Campanian Cambrian Silurian Devonian Permian Triassic Jurassic Cretaceous 75 vician ferous gene gene 77 Hod Fm. 79 Late 82 Santonian 542 488 444 416 359 299 251 200 145.5 65.5 0 84 Coniacian 86 million years 88 Turonian 91 93 Cenomanian 95 97 99 102 Albian 105 108 112 Cretaceous 115 Aptian 118 Early 122 125 Barremian 128 Hauterivian Paleo- Meso- 132 2 000 1 000 0 Valanginian zoic zoic 135 million years 138 Berriasian 142 145 Tithonian Draupne Fm. Stord Basin Jurassic Model Geological time scale 148 Late Kimmeridgian 152 Ula Fm. Stord Basin Mounds * 155 Oxfordian 158 Callovian 162 Hugin Fm. Hugin East Bathonian Sandnes Fm. 165 Middle Bajocian Sleipner Fm. Bryne / Sandnes Formations South * 168 Brent Gp. Bryne Fm. Aalenian Bryne / Sandnes Formations Farsund Basin 172 175 Jurassic Toarcian 178 Johansen Fm. 182 Johansen and Cook Formations * Pliensbachian Cook Fm. 185 Early 188 Sinemurian 192 195 Hettangian Statord Gp. Nansen Eiriksson Raude Gassum Fm. 198 Rhaetian Gassum Fm. 202 205 Skagerrak Fm. Norian 208 212 Late 215 218 riassic Carnian Formations not 222 T evaluated 225 228 Middle Ladinian 232 * Evaluated prospects 31 4.1 Geology of the North Sea The basic structural framework of the important seal for hydrocarbon traps in North Sea is mainly the result of Upper the North Sea area. Jurassic/ Lower Cretaceous rifting, Cretaceous: The rifting ceased and partly controlled by older structural was followed by thermal subsidence. elements. The Upper Cretaceous in the North Carboniferous-Permian: Major Sea is dominated by two contrasting rifting with volcanism and deposition lithologies. South of 61o N there was of reddish eolian and fluvial sandstones deposition of chalk, while to the north (Rotliegendes). Two basins were devel- the carbonates gave way to siliclastic, oped with deposition of thick evapo- clay-dominated sediments. rate sequences (Zechstein). When over- Cenozoic: In the Paleocene/Eocene lain by a sufficient amount of younger there were major earth movements sediments, buoyancy forces caused with the onset of sea floor spreading in the salt to move upwards (halokinesis). the north Atlantic and mountain build- This is important for generation of ing in the Alps/Himalaya. In the North closed structures, including hydrocar- Sea, deposition of chalk continued bon traps, in the southern part of the until Early Paleocene. Uplift of basin North Sea and also as a control on local margins, due to inversion, produced a Geoseismic cross section in the northern North Sea. topography and further sedimentation. series of submarine fans transported From the Millennium atlas 2001 Triassic: Major N-S to NE-SW rifting from the Shetland Platform towards with thick coarse fluvial sediments de- the east. These sands interfinger with posited along rift margins, grading into marine shales in both the Rogaland finer-grained river and lake deposits in and the Hordaland Groups. In the Mio- the center of the basins. The transition cene a deltaic system had developed between the Triassic and Jurassic is from the Shetland Platform towards marked by a widespread marine trans- the Norwegian sector of the North Sea, gression from north and south. and is represented by the Skade and Jurassic: The marine transgression Utsira Formations. Due to major uplift was followed by the growth of a volca- and Quaternary glacial erosion of the nic dome centered over the triple point Norwegian mainland, thick sequences between the Viking Graben, the Central were deposited into the North Sea Graben and the Moray Firth Basin. The during the Neogene. This led to burial doming caused uplift and erosion, and of the Jurassic source rocks to depths was followed by rifting. Large deltaic where hydrocarbons could be generat- systems containing sand, shale and ed and the seals were effective. coal were developed in the northern North Sea and the Horda Platform (Brent Group). In the Norwegian-Dan- ish Basin and the Stord Basin, the 62° Vestland Group contains similar deltaic sequences overlain by shallow marine/ 61° B marginal marine sandstones. The most B’ important Jurassic rifting phase in the North Sea area took place during the 60° Late Jurassic and lasted into the Early Cretaceous. During this tectonic epi- 59° sode, major block faulting caused uplift and tilting, creating considerable local 58° A’ Geoseismic cross section in the Egersund basin. topography with erosion and sediment A From the Millennium atlas 2001 supply. In anoxic basins thick sequenc- es of shale accumulated, producing the 57° most important source rock and also the Draupne Formation, which is an 56° 2° 3° 4° 5° 6° 7° 8° 9° CO2STORAGEATLAS NORWEGIAN CONTINENTAL SHELF 32 4.1 Geology of the North Sea faciesmap Bajocian faciesmap Mid- to late Callovian Well log 33/9-1 62° 62° ? ? 34 35 34 35 ? 30 31 30 31 32 ? ? ? 25 Arch Vestland 26 27 25 Stord 26 27 Basin Utsira High ? 16 17 18 Sele V 16 17 18 High ? Egersund Basin ? 7 8 9 10 7 8 9 10 ? ? 6° Examples of mid Jurassic relationship between continental and marine deposits in central and northern North Sea. Continental sediments in brownish colour, shallow marine in yellow and offshore marine in blue. The map to the left displays the development of the Brent delta and the early stage of the deposition of the Bryne Formation. The map to the right shows the development of the Sognefjord delta and the Sandnes and Hugin Formations after the Brent delta was transgressed. 33 4.1 Geology of the North Sea 62° 62° Depth to the mid Jurassic Depth to the top Jurassic 270 m 300 m 5600 m 6800 m Brent Gp Faults 61° 61° Bryne Fm Sogneord Fm Sleipner Fm Hugin Fm (east) Faults Hugin Fm (west) Jæren graben Sogneord equivalent Contour interval 200 m Sandnes Fm Ula Fm 60° 60° Contour interval 200 m 59° 59° 58° 58° 57° 57° 56° 56° 2° 3° 4° 5° 6° 7° 8° 2° 3° 4° 5° 6° 7° 8° Mapping of the upper and middle Jurassic forms the basis of many of the following depth and thickness maps of assessed geological formations.