Imaging Reservoir Geology of the Troll West Field in the North Sea by 3D Seismic Interpretation

Abstract

The Troll Field is called super giant gas field . This is the second largest gas field of offshore Europe with its 1670 billion m3 of gas and 615 million m3 of oil initially in place. The Troll Field was discovered in 1979 and located about 80 km offshore Norway on the northwestern edge of the Horda Platform and eastern edge of the Viking graben in the water depth of 300 355 meter. The total area of the field is about 710 km2 and extends over four Norwegian Blocks (31/2, 31/3, 31/5 and 31/6).The reservoir successions contain the Sognefjord, Fensfjord, Heather and Krossfjord Formations of the Jurassic Viking Group. Deposition occurred as a cyclic sequence of shallow marine sand stone with alternations of transgressive and regressive shoreface facies. The main goal of this study is detailed integrated seismic and well data study of reservoir units to determine the reservoir distribution and depositional environments.The main reservoir unit is the Sognefjord Formation and contains about 90% of the field hydrocarbon reserves. This Formation is seismically characterized by low angle clinoforms and the seismic data shows westward Progradation. The Flat Spot is the prominent characteristic of the seismic data. The Sognefjord, Fensfjord, and Krossfjord formations interpreted as tide, wave and fluvial dominated environment.