In geology, a group is a lithostratigraphic unit consisting of a series of related formations that have been classified together to form a group. Formations are the fundamental unit of stratigraphy. Groups may sometimes be combined into supergroups .
18-659: The Nanushuk Formation or Nanushuk Group is a geologic group in Alaska in westernmost National Petroleum Reserve in Alaska (NPR-A). Petroleum in these rocks likely was generated beneath Western Alaska North Slope and migrated northeastward into NPR-A. The formation preserves fossils dating back to the Albian - Cenomanian ages of the Cretaceous period . Its thickness varies from about 1500 to about 250 meters. Underneath
36-644: A final investment decision on the project was still pending. In May 2024 Repsol and Santos Limited subsidiary Oil Search were looking to sell 20-25% of their non-operating interest in the Pikka unit. one month after they had asked for a permit to hydraulic fracking . In 2022, the Alaska Department of Natural Resources Division of Oil and Gas approved that Oil Search forms and operates the Horseshoe unit. In 2017, ConocoPhillips announced discovery of
54-601: A noticeable majority, 59% of the finds near the Kukpowruk River . Before 2015, over a period of more than 50 years about 150 oil exploration wells had been drilled into the Nanushuk and Torok Formations, yet oil production had had almost zero success finding one small oil pool with less than 50 million barrels in place. However, as of 2017, the U.S. Geological Survey estimated that there were 8.7 billion barrels of oil and 25 trillion cubic feet of natural gas in
72-406: A project's lifecycle (i.e., the front end of a project), at a time when the ability to influence changes in design is relatively high and the cost to make those changes is relatively low. It typically applies to industries with highly capital intensive, long lifecycle projects (i.e., hundreds of millions or billions of dollars over several years before any revenue is produced). Though it often adds
90-473: A small amount of time and cost to the early portion of a project, these costs are minor compared to the alternative of the costs and effort required to make changes at a later stage in the project. It also typically uses a stage-gate process, whereby a project must pass through formal gates at well defined milestones within the project's lifecycle before receiving funding to proceed to the next stage of work. The quality of front-end planning can be improved through
108-483: Is the process for conceptual development of projects in processing industries such as upstream oil and gas , petrochemical , natural gas refining , extractive metallurgy , waste-to-energy , biotechnology , and pharmaceuticals . This involves developing sufficient strategic information with which owners can address risk and make decisions to commit resources in order to maximize the potential for success. Front-end loading includes robust planning and design early in
126-586: The Glenwoody Formation , other strata (particularly in the lower part of the group) remain undivided into formations. Some well known groups of northwestern Europe have in the past also been used as units for chronostratigraphy and geochronology . These are the Rotliegend and Zechstein (both of Permian age); Buntsandstein , Muschelkalk , and Keuper ( Triassic in age); Lias , Dogger , and Malm ( Jurassic in age) groups. Because of
144-660: The Torok Formation below it forms a huge wedge of sediment deposited in a deep water basin and stretches from north of the Brooks Range beneath the Alaska North Slope to the adjacent offshore. It was deposited in shallow water and includes potential reservoirs in deltaic , shoreface , and fluvial sandstones. The USGS found large-scale folds and faults in the South of the formation and evidence, that
162-721: The Willow oil pool in the Nanushuk Formation with estimated resources of more than 300 MMBO. The Nanushuk was reduced in rank from geologic group to geological formation and many of its subunit terms were completely abandoned. The Corwin Formation, Chandler Formation along with its members the Killik Tongue, and Niakogon Tongue, were all reassigned to the upper or nonmarine section of the Nanushuk. The Grandstand Formation and Topagoruk Formation were reassigned to
180-866: The Wingate Sandstone , the Moenave Formation , the Kayenta Formation , and the Navajo Sandstone . Each of the formations can be distinguished from its neighbor by its lithology , but all were deposited in the same vast erg . Not all these formations are present in all areas where the Glen Canyon Group is present. Another example of a group is the Vadito Group of northern New Mexico . Although many of its strata have been divided into formations, such as
198-429: The Nanushuk and Torok Formations, much more than previously estimated. These discoveries were possible, because of technological advancements like three-dimensional seismic data processing , extended reach drilling . In 2013, Repsol and Armstrong Energy discovered the Pikka oil field by drilling a discovery well they called Qugruk 3. In 2015, they announced the Pikka oil pool to the public. In 2017, an extension of
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#1732773351991216-509: The Nanushuk lies the Torok Formation . Until 2015, for more than 50 years about 150 oil exploration wells had had almost zero success; However, in 2015, Repsol announced the Pikka oil pool and in 2016, ConocoPhilips announced the Willow project . As of 2017, the U.S. Geological Survey estimated that there were 8.7 billion barrels of oil and 25 trillion cubic feet of natural gas in the Nanushuk and Torok Formations, much more than previously estimated. The Nanushuk Formation together with
234-506: The confusion this causes, the official geologic timescale of the ICS does not contain any of these names. As with other lithostratigraphic ranks, a group must not be defined by fossil taxonomy. Front-end engineering and design Front-end loading (FEL), also referred to as Front End Planning (FEP), pre-project planning (PPP), feasibility analysis , conceptual planning , programming/schematic design and early project planning ,
252-440: The middle or transitional portion between the lower marine and upper nonmarine. The Kukpowruk Formation, Ninuluk Formation, and Tuktu Formation were reassigned to the lower marine section. The Hatbox Tongue's name was changed to the Killik Tongue, both terms are no longer in use. Group (geology) Groups are useful for showing relationships between formations, and they are also useful for small-scale mapping or for studying
270-580: The rocks have been heated to temperatures at which oil is converted to natural gas. The thickness of the Nanushuk Formation varies from about 1500 to about 250 meters. The formation preserves fossils dating back to the Albian - Cenomanian ages of the Cretaceous period . Many fossilized dinosaur footprints and wood fragments have been found in this formation. Some tree trunks reached up to 58 cm in diameter. Ichnotaxa of Nanushuk Formation include avian and non-avian theropods , quadrupedal ornithischians and bipedal ornithischians. The latter make up
288-435: The same oil pool at "Horseshoe", 21 miles south of the Pikka discovery was confirmed. Per USGS in 2017, industry estimated this Pikka-Horseshoe pool may hold more than 1,000 million barrels of oil (MMBO). In 2017 Armstrong sold its interests to Oil Search , an Australian-listed oil and gas company. The so called "Nanushuk development project" is operated by Oil Search at 51% interest, and Repsol at 49% interest. More remarkable
306-468: The stratigraphy of large regions. Geologists exploring a new area have sometimes defined groups when they believe the strata within the groups can be divided into formations during subsequent investigations of the area. It is possible for only some of the strata making up a group to be divided into formations. An example of a group is the Glen Canyon Group , which includes (in ascending order)
324-524: Was the pervasive presence of bioturbation with worm burrows crossing between the silts and sands. Under normal circumstances vertical flow would be much reduced in stacked silt and shale sequences but the bioturbation was sufficient to guarantee efficient vertical recovery. In 2020, the Pikka Unit was expected to be the first development project to begin oil production in the Nanushuk formation, when Front-end engineering and design had started, though
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