Compaction model for quartzose sandstones application to the Garn Formation, Haltenbanken, Mid-Norwegian Continental Shelf

The compaction of quartzose sandstones is described by a macroscopical visc o-elasto-plastic model, derived from microscopical considerations. This mod el considers that the reduction of total porosity (the relative pore volume ) is related to the chances in the relative cemented volume and the relativ e intergrain volume. Furthermore, we consider that the variations of these two petrophysical parameters result from two physical mechanisms, mechanica l compaction and closed system chemical compaction. The model has been calibrated for the Middle Jurassic Gam Formation from th e Haltenbanken area of the Mid-Norwegian Continental Shelf. Around 300 data points from 17 wells have been used in this study, The viscous parameters have been optimised against the present day data. With total porosity data the best fit is obtained for an activation energy between 14 and 16 kJ/mole and a macroscopical. viscosity at 15 degreesC between 39 and 46 Gpa . Ma ( 1.210(24)-1.410(24) Pa.s). If quartz cement data are used, tile best fit is obtained for an activation energy between 16 and 18 kJ/mole and a macrosco pical viscosity at 15 degreesC between 47 and 56 Gpa . Ma (1.510(24)-17.10( 24) Pa.s). The visco-elasto-plastic compaction model has been tested in the Haltenbank en area of Mid Norway, with the result that observed porosity trends and po re pressures can be modelled. Using multiple 2-D basin modelling simulation s the results of this model and its implications for fluid flow and petrole um systems analysis can be seen. The compaction method has significant impa ct on the simulated fluid flow and petroleum migration pattern. (C) 2001 El sevier Science Ltd. All rights reserved.