Norne Field, in the southern part of the Nordland II area in the Norwegian Sea approximately 100 km north of Aasgard Field, is producing from an FPSO. The main field is a horst block approximately 9 ǂ 3 km (Figure 1). The reservoir rocks are sandstones of Lower and Middle Jurassic age. The hydrocarbon reserves consist of a gas cap (75 m), mainly situated in Garn Formation, and an oil leg (110 m), mainly situated in Ile and Tofte formations. The sandstones are very good quality with porosities and permeabilities of 25-32% and 200-2000 mD, respectively. Net-to-gross is close to 1 for most reservoir zones. Oil production started in 1997. The first 4D seismic survey was acquired in 2001, and 4D information has been actively used in subsequent reservoir management. This paper will focus on the importance of tight integration of all disciplines for achieving good quality and repeatable 4D seismic data that can optimize new drilling targets and help obtain a more reliable reservoir simulation model.

Duringreservoirm odelbuilding, onee ncounters severals tagesw hereupscalingor averagingof petrophysicaldatai sr equired;coreplugd atah aveto be compared to wirelinemeasurements andwireline measurementsareaveraged to the scaleofbuilding-sizereservoirgrid cells. Simpleaveragingdoesnot,inmost cases,giverepresentativevalues,since the property inquestion isvery scale-dependent. Thisisespecially true for permeability andpermeability anisotropy( k v / k h ).For the caseofareservoirm odelo fthe Garn Formation (MiddleJ urassic)int he Tyrihans Field, asimple geologically based upscalingmethodi ncludingthe useofthe SBEDe softwarepackage hasbeendeveloped. Small-scalemodels ofnearw ell-boreg eologyareupscaled usingsingle-phasefl ow simulation to obtain directional-dependent permeabilitiesfor faciesw ithd ifferent mudc ontents andstyle.The resulting k v / k h estimation curvehasbeenimplemented inthe reservoirmodelbymodelling V shale asacontinuous parameterand applyingthe function to deriveupscaled horizontalandverticalp ermeability grids. Upscaled permeabilities werefoundto closely match the well test data.Thisapproach givesamorerealistic k v / k h ratiot hant raditionalm ethodsinvolvingsimplea veraging, or arbitrary guesses,ofverticalpermeability.

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