3D Geological Model of the Garn and Not Formations in Norne Field, Mid-offshore Norway

Abstract

Norne Field is one of the hydrocarbon fields in the Norwegian Sea. This field has an area of approximately 9km x 3km which lies in the transition between two structural elements that are the Dønna Terrace and the Nordland Ridge. The main reservoir of Norne Field is in the Jurassic Sandstones. The hydrocarbons were mainly found in the Ile, Tofte, Garn, and Not Formations. This study will focus on the Middle Jurassic intervals which are the Not and the Garn Formations.

The objective of the study is to create a 3D geological model through the integration of well logs, cores, and 3D seismic interpretation to provide the better understanding of the geological settings, in which, depositional environments, fault network, and stratigraphy.

Garn and Not Formations are siliciclastic sediments deposited in the shallow marine environment. In the seismic data, the top of the Middle Jurassic reservoir is Top of Garn Formation in the northeastern part of the area and Top of Not Formation in the southwestern part. There is a facies change that is represented with a pinch out geometry observed in the seismic horizon interpretation and further confirmed by the well data, as well as by the seismic facies analysis. Two sources area has been predicted as the source of the sediment in these two formations. Based on the well log and core interpretation, the sediments in the Not Formation came from the southwestern source which prograded in the northeastern direction. The Garn formation is predicted to come from northeastern source area and prograded in the southwestern direction.

The structural setting of the Norne Field is dominated by extensional structure. One horst block which was predicted formed around the late Middle Jurassic until the Early Cretaceous formed the major structure of the Norne Field. The major faults in the study area are oriented NE-SW with some minor fault oriented NW-SW.