Njord Field

Fig. 2. Photo-micrograph of fault structures from the Njord Field, Haltenbanken. (a) Micro-fault zone characterized by dense packing of grains only, (b) Micro-fault zone characterized by dense packing of grains and phyllosilicate enrichment. Dissolution of quartz occur at grain contact with mica (arrow), (c) Micro-fault zone with abundant stylolites.

The Njord Field is located at Haltenbanken 30 km west of the Draugen Field at a water depth of 325 m. The field was discovered in 1985. Plans for the development and operation of the field were submitted to the authorities in Spring 1995 and planned production start-up is Autumn 1997. The expected recoverable oil reserves for the main production phase are estimated to be 32 MS m. ... 

A proper understanding of the above items, including maturation and filling history, formation pressure distributions, intra-reservoir communications, fault and top seal potentials, and leakage mechanisms, is considered essential for resource assessment, safe drilling of further explora-tion/delineation and production wells, and for reservoir management and production planning of the Njord Field. 

The interplay between reservoir and cap rock pore-pressures and vertical leakage mechanisms for the field has been further assessed by analysing the reservoir pore-pressure situation at the apex (i.e., the weak point ) of each hydraulic compartment (Fig. 13), and by relating the apex reservoir pore-pressures to the corresponding minimum fracture pressures of the cap rock (Fig. 14). The fact that the Spekk Formation represents both the main source rock and cap rock for the Njord Field is a key aspect in these considerations. 

Lilleng, T. Gundeso, R. 1997. The Njord Field, a dynamic hydrocarbon trap. Im. Moller-Peder-sen, P. Koestler, a. G. (eds) Hydrocarbon Seals—Importance for Exploration and Production. Norwegian Petroleum Society (NPF) Special Publication, 7, 201-217. 

The pore-pressure profiles further show that pressure equalization has been reached between the Jurassic reservoirs and the lowermost Cretaceous-Upper Jurassic caprock of the Njord structure as there is no drop in pressure when entering into the Jurassic reservoir units (as seen in many other fields on Halten-banken Koch and Heum, 1995). 

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