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dc.contributor.authorKjølstad, Christopher
dc.date.accessioned2014-11-10T23:01:11Z
dc.date.available2015-06-02T22:30:07Z
dc.date.issued2014
dc.identifier.citationKjølstad, Christopher. Reservoir quality, diagenesis and depositional environments of Early Jurassic sandstone reservoirs located in the northern North Sea, Knarr area. Master thesis, University of Oslo, 2014
dc.identifier.urihttp://hdl.handle.net/10852/41565
dc.description.abstractThe Early Jurassic Cook sandstones from the northern North Sea, Knarr area have been investigated to provide information of the reservoir quality. Four cored wells, 34/3-2 S, 34/3-1 S, 34/3-3 S and 34/5-1 S, have been analyzed and observed in the manner of sedimentology, mineralogy and petrography. The main focus has been on the relation between the formation of the precursor of chlorite coating and the depositional environment. Four Facies associations have been interpreted from the five sandstones, C1, C2, C3, C4 and C5, in the cored intervals from the four wells; Nearshore delta slope deposits, Tidal compound dunes, Tidal bars and Offshore deposits. All the deeply buried sandstones in the Knarr area, which is situated around 3500 m bsf show anomalously high porosities. There are observed minor amounts of quartz cement, due to retardation by the chlorite coating. Chlorite, kaolinite and illite are the three dominant clay minerals in the sediments. Much of the fine-grained constituents were deposited as detrital mud drapes and subaquatic infiltrated mud clogs. The detrital clay minerals also formed the precursor (i.g. berthierine) of the iron rich chlorite coating (i.g. chamosite). The Cook sandstones in the Knarr area are interpreted to have been deposited in a pro delta-delta slope environment as tidal bars and compound dunes. The sandstones have experienced reworking in different stages by the tidal dominated environment. Subaerial exposure of the tidal bars and compound dunes are interpreted to have created a vadose zone. The formations of the precursor to the chlorite coating on the detrital grains are suggested to have occurred in a vadose zone. Subaquatic infiltration of fine-grained constituents has also been suggested as a reason for the formation of the precursor. The origin of the precursor is of great importance because the precursor is the link between the chlorite coating and the depositional environment.eng
dc.language.isoeng
dc.subjectChlorite
dc.subjectcoating
dc.subjectNorthern
dc.subjectNorth
dc.subjectSea
dc.subjectDepositional
dc.subjectenvironment
dc.subjectDiagenesis
dc.titleReservoir quality, diagenesis and depositional environments of Early Jurassic sandstone reservoirs located in the northern North Sea, Knarr areaeng
dc.typeMaster thesis
dc.date.updated2014-11-11T23:00:05Z
dc.creator.authorKjølstad, Christopher
dc.identifier.urnURN:NBN:no-46068
dc.type.documentMasteroppgave
dc.identifier.fulltextFulltext https://www.duo.uio.no/bitstream/handle/10852/41565/1/Master-thesis---Christopher-Kjoelstad.pdf


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