Unlocking the Potential of the Nordkapp Basin and the East Barents Sea: An Integrated Approach

Miles Dyton

The Nordkapp Basin is an intra-continental syn-rift basin containing many complex salt structures. The salt is late-Carboniferous to early Permian in age, with regional extension in the Triassic initiating the salt movement, and subsequent tectonic phases allowing growth and distortion of these diapirs. Subsequent uplift and erosion in the Tertiary has resulted in the generation of salt-related traps in the Triassic and Lower Jurassic. These structures are notoriously hard to image with conventional techniques due to the generation of strong multiples from the sea floor and the top of the shallow salt structures. Seismic shadow zones and structures within the salt (possibly shale and carbonate rafts and stringers) cause severe diffractions and prospective areas adjacent to the salt remain elusive. Few wells have been drilled in the Nordkapp Basin of which two were in the western basin: 7228/7-1 was a small oil and gas discovery; and 7227/11-1 did not find reservoir. The prognosis for a functioning hydrocarbon system in the Nordkapp Basin is good, and hydrocarbon charge modeling will be important in assessing the prospectivity of potential targets. Arctic exploration is expensive and the ability to focus on the highest potential targets is essential. WesternGeco has developed a unique solution to this challenging subsurface Arctic environment by integrating Petroleum Systems Modelling and Play Chance Mapping with highly efficient full-azimuth broadband seismic acquisition and processing. This integrated approach allows intelligent location of seismic surveys over structures which have the maximum chance of success of hydrocarbon charge. The evaluation and assessment of the petroleum system is achieved through use of Schlumberger’s PetroMod software. The combination of WesternGeco’s Coil shooting and ObliQ sliding notch acquisition and imaging technology provides a reliable and cost effective method of acquiring full azimuth broadband data with a single vessel using Q-Marine point receiver steerable streamer technology. This integration ensures that exploration effort is focused on identifying and mapping the structures with the highest potential. WesternGeco acquired a full azimuth Coil ObliQ broadband seismic survey over Block 7231/2 in the Nordkapp Basin in 2012 close to the limit of permitted exploration. The resulting seismic data has allowed mapping of salt walls, traps, and overhanging structures never before seen in this region. Further deployment to the East is planned when this area is open for exploration. This integrated approach to locating seismic surveys in frontier regions may be adapted for exploration elsewhere in the Arctic, onshore or offshore, or anywhere else that requires intelligent placement of advanced acquisition techniques to maximize the potential for success.

AAPG Search and Discovery Article #90177©3P Arctic, Polar Petroleum Potential Conference & Exhibition, Stavanger, Norway, October 15-18, 2013