Triassic Hydrocarbon Source and Reservoir Rocks of Svalbard and the Barents Sea

Atle Mørk

During the Triassic Period, hydrocarbon source rocks and overlying sandstones were deposited forming potential plays in large parts of the Barents Sea Shelf. Equivalent beds are seen to occur in the excellent Triassic exposures of Svalbard and several stratigraphic cores in the Northern part of the Barents shelf have also penetrated these units. These wells have been drilled by the Norwegian Petroleum Directorate in the north and in the southern part by IKU/SINTEF Petroleum Research. The combination of seismic data and exploration wells in the southern Barents Sea comprises an excellent database for evaluating the remaining areas of the Barents Sea presently being explored. The Barents Shelf with Svalbard originally formed within a major embayment on the northern coasts of the Pangea supercontinent. This sea was gradually filled with sediment from the newly folded Uralian Mountains during the Triassic. Lower and Middle Triassic organic rich mudstones were subsequently drowned by prograding delta systems that eventually filled the entire embayment. In the latest Triassic and Early to Middle Jurassic, the basin was filled and the sandstones were maturated to form good reservoir sands. We will short summarise features related to the petroleum potential of the Barents Shelf. The Late Early and Middle Triassic have prolific marine hydrocarbon source rocks. In the Late Triassic well developed growth faults probably represent delta front deposition and slope failure. Hopen islands steep mountain sides display channels of seismic scale, as well as 20 smaller sandstone bodies might add to the overall reservoir potential (see poster). Triassic successions in the Barents Sea area reveal palynological assemblages forming 15 composite assemblage zones applicable for regional correlation (see poster). Insight into fracture densities of varying sandstone facies and regional trends throughout Svalbard. Additional local sediment source areas also existed, and one example of westerly sourced deltaic and shallow marine sediments is found on south western Spitsbergen. Triassic clinoform belts are identified on seismic data and tied to exploration wells and stratigraphic cores. They prograde northwards through the Barents Shelf, becoming successively younger from SE to NW.

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