Geology

The Norwegian Sea rose to geological fame in 1981 with the discovery of Midgard - now part of Åsgard - and swiftly became a key petroleum province, mature and active today with several oil and gas fields in production. Recent discoveries in diverse plays such as the Egyptian Vulture, Black Vulture, Slagugle, and Iris/Hades have proven the Norwegian Sea's considerable continued potential. 

PGS has operated several seismic acquisition campaigns in the Norwegian Sea since 2010 and developed refined acquisition parameters as well as processing workflows to provide high-resolution GeoStreamer coverage. The Norwegian Sea multisensor datasets address a variety of subsurface imaging challenges to provide an accurate representation of the subsurface and improve the geological understanding of the area. 

Untapped and Underexplored Proven Reservoirs of the Norwegian Sea

PGS' Norwegian Sea datasets cover a variety of petroleum play models relevant in mature, infrastructure-led exploration to less tested plays within structural provinces bordering the Trøndelag Platform, the Halten and Dønna terraces, and extending into the outboard Rås and Træna basins. 

Historically, main reservoir targets have been good-quality Jurassic sandstones in structural traps, with little attention to the Cretaceous.

Norwegian_Sea_Geosection
An arbitrary line geosection through the central-southern Norwegian Sea, highlighting stratigraphy. Click the image for more information on structure and various proven reservoir sections. 

However, over the last decade, improved seismic data quality has led to an increasing focus on deep-marine clastic fan systems and stratigraphic traps in the Cretaceous section. 

In terms of prospectivity, the Norwegian Sea still has undrilled Jurassic structures, and the Upper Jurassic and Cretaceous deep marine system is underexplored in some areas. This together with exploration potential within the Paleocene and Triassic makes this area attractive for continued exploration. 

New Opportunities in Outboard Frontier Areas

The Norwegian Sea PURE GeoStreamer data delivers seamless, high-quality seismic coverage over much of the prolific provinces of the Norwegian Sea and provides high-resolution images to accurately map complex fault zones and often deep Jurassic structural traps. Subtle stratigraphic features in the Cretaceous are resolved to trace deep water depositional systems in a source-to-sink interpretation approach. 

Outboard frontier areas can offer new opportunities extrapolating Cretaceous deep water sand plays such as the Vigrid-Nyk High area  - a combination of interpretation and pre-stack attribute analysis highlights prospects as shown in the image below. 

Nyk High_Cretaceous
3D display of incoherence attribute on Late Cretaceous top Nise horizon with Vp/Vs ratio overlay highlighting existing gas and condensate discoveries and fields (perspective view towards N across the Nyk High).

Extension of known trends into new areas provides access to established plays and options to evaluate new exploration ideas, e.g., 3D GeoStreamer over the Nordland Ridge. New data in frontier areas such as the Trøndelag Platform covered by the 'elephant' project offer unprecedented insights into the subsurface and challenge perceptions about the viability of potential plays such as the Paleozoic by affording new source rock interpretations.

Rock Physics Modeling

Complementary to improved seismic understanding in the region, an interactive rock physics modeling product, rockAVO, is available to integrate seismic with well data. The rockAVO database includes more than 150 wells covering the main Triassic-Cretaceous stratigraphic intervals through the Jurassic sequence of the Norwegian Sea. This interactive, real-time rock physics modeling tool allows us to model seismic responses based on the variation of a number of reservoir parameters such as volume of shale porosity and hydrocarbon saturation. 

The well data delivered in rockAVO provides consistent petrophysical logs, rock physics models, and interactive seismic AVO modeling capabilities for each well In the area. Linking the rockAVO to the PGS MultiClient data library makes it possible to calibrate GeoStreamer and other seismic data with conditioned well data and known production scenarios. 

Rock physics properties vary from basin to basin, and between stratigraphic intervals. For each, a separate model or rock physics template has been calibrated to relate the seismic response to rock and fluid properties. 

Exploration and production companies can now access a homogeneous database of interpreted well logs throughout the Norwegia Sea, making it possible to analyze the seismic AVO signature based on different fluid and matrix property perturbations and by using it as a well analogue for other areas and/or identified leads. 

Norwegian_Sea_rockAVO_example
A rockAVO example dataset from the Norwegian Sea - click the image for more information.