Verweij, Hanneke¹, Pascal Winthaegen¹, Erik Simmelink¹, Barthold Schroot¹ 
(1) Netherlands Institute of Applied Geoscience TNO - National Geological Survey, 3508 TA Utrecht, Netherlands

ABSTRACT: Integrated Prediction of Pressures and Fluid Flow in the Netherlands Central North Sea Graben

The Netherlands Institute of Applied Geoscience TNO - National Geological Survey investigates a combination of different methods to estimate pore pressure distributions and fluid flow in sedimentary basins. This paper focuses on the combined application of seismic methods and 2D basin modeling. It discusses examples of predicted pressure distributions and related fluid flow conditions in the Netherlands Central North Sea Graben. 
Severely overpressured conditions are known to occur in the Chalk Group, especially in the northern part of the Graben, and in the syn-rift reservoir units of Late Jurassic -Early Cretaceous age and the Triassic early-rift units. Basin boundary faults and salt structures laterally restrict these syn-rift and early rift units. To date no pressure information is available for the Tertiary. 
One of the seismic methods involves the application of the Eaton method to calibrated sonic well information and 3D seismic interval velocity data. This method was used to identify, amongst other things, undercompaction and overpressuring within the Lower Tertiary shales. We also interpreted 2D and 3D seismic data and acoustic data to detect fluid flow, for example by identifying seismic chimneys indicative of upward flow of fluids or free gas. Seismic chimneys were detected in Tertiary and Quaternary units in the northern part of the Graben. 2D Basin modeling (Petromod) was used to provide additional predictions of present-day pore pressure and fluid flow distributions and to evaluate the factors responsible for the pore pressures and fluid flow detected by the seismic methods.

AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.