Geodynamics and Basin Studies

Estimation of geocell water saturation based on small-scale structures in the Brent Group on the Oseberg and Gullfaks fields

Master student: Ingrid Dalland

Supervisors: Jan C. Rivenæs and William Helland-Hansen


Water saturation in reservoir rocks is highly dependent on petrophysical parameters as permeability, porosity and the amount of clay and shale in the sandstone. Saturations are important for static hydrocarbon volumes and for saturation-dependent flow parameters, such as relative permeabilities. Methods used today to estimate water saturation are usually based on petrophysical logs with low resolution and simplifications of the nature of the reservoirs. In reservoir computer models, saturations are implemented as mathematical relations (Leverett J functions). This makes water saturation a quite uncertain property.

The aim of this thesis is to try to provide improvements to the water saturation modelling on intervals with extensive small-scale structures. This will be based on cores and core plugs from selected intervals on Oseberg and Gullfaks and models that will be modelled in SBED™. SBED™ technology models the small-scale sedimentary details that impact large-scale reservoir performance. The thesis is interdisciplinary oriented with elements from sedimentological description, petrophysical measurements and reservoir technical considerations.