Geological interpretation and well log analysis of F3 block, North Sea (T-1484) (MFN 4303)

Abstract

The area under study is included in the Central Graben of southern North Sea which comes under Netherland’s sector of North Sea. The 3D seismic survey (F3 block) was done in 1989 by NAM, a Dutch oil and gas company. 3D data contains 650 inlines and 950 crosslines. The research project is divided into three parts. The first objective of the research was to interpret the sequences models on the seismic data. Spectral decomposition attribute is used for the identification/delineation of sequence boundaries. Four system tracts were identified with shale sand sequences on seismic section including the Transgressive System Tract, High Stand System Tract, Falling Stage System Tract and Low Stand System Tract. In order to get the thicknesses of these system tracts, thickness maps were generated. Secondly, structural analysis was carried out on the data set. Seismic attributes have been used for the identification of reflectors and faults. Upper North Sea Group Formation has been marked and mapped on the seismic data which is acting as a reservoir in the area. Time contour and depth contour maps were generated for the horizon to determine the structural trend in the area. Lastly wireline log data have been used for the well correlation and petrophysical analysis. Well correlation was done in which four wells were cross plotted demarcating the thicknesses and lateral continuity of four system tracts. Petrophysical analysis was done afterwards in which the well was divided into different zones. Results calculated with the help of available data revealed that all the zones were water saturated having no amount of hydrocarbons in it.