TECTONIC-SEDIMENTARY EVOLUTION OF JURASSIC IN VIKING GRABEN,THE NORTH SEA

The Jurassic contains the major source rock in the Viking Graben,with shallow-marine sandstones and deep-water submarine-fan sandstones as main reservoirs.Careful study of tectonic-sedimentary evolution is the key to oil and gas exploration.The Jurassic in the Viking Graben could be divided to two phases: Early-Middle Jurassic thermal subsidence and Late Jurassic active stretching phases.In the early stage of the thermal subsidence phase,marine depositional environments prevailed.But in the Middle Jurassic stage it is dominated by a non-marine delta depositional system.In the phase of active stretching,there formed a deep-water submarine-fan system.Based on the facts mentioned above,two tectonic-sedimentary models were established for the Jurassic in Viking Graben of the North Sea.