• Previous production branches were cut short after exiting the Sognefjord reservoir
  • A heterolithic reservoir consisting of alternating micaceous sands and unconsolidated sands
  • Micaceous sands had poorer reservoir quality and different resistivity when compared with unconsolidated sands
  • Oil/water contact varied considerably in the reservoir
  • Monitored the oil/water contact continuously and kept the wellbore at desired standoff
  • Identified the top of the Sognefjord using real-time inversion up to 39 ft (12 m) above the wellbore
  • Gained more than 984 ft (300 m) of saturated oil reservoir after drilling strategically into a water zone
  • Successfully drilled an 11,237-ft (3425-m) horizontal section with an average ROP of 128 ft/hr (39 m/hr) while using proactive reservoir navigation techniques

Case study details

The Troll field off the shore of Norway is one of the largest natural gas and oil fields in the Norwegian sector of the North Sea, holding 40% of Norway’s gas. The area west of the field also possesses significant quantities of oil in thin zones under the gas cap.

The reservoir is located in three eastward-tilted fault blocks 4,921 ft (1500 m) below sea level. It consists of cyclic sandstones from the Fensfjord, middle Heather, Sognefjord, and upper Heather formations in the Jurassic Viking group, and is overlaid by Upper Jurassic to Paleocene clays.

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