For the new Snorre Geo- and Simulation model, a re-evaluation of the petrophysical input was necessary. The database of 31 cored wells (of a total of 105 wells evaluated for the model) gave the opportunity to establish a new method for determining net reservoar based on the neutron porosity and density logs, calibrated to UV photographs of oil leg core. This metod has been compared to the conventional metod based on a 1 mD core permeability cutoff. The database contains wells having been drilled over a more than 20 year time span, with a range of different neutron porosity and density logs used in a variety of logging environments. Both for determining net reservoir and for porosity there was a need to establish a methodology to be able to compare and normalize the logging responses for the evaluation. Complicating the matter, the data span a depth range of more than 1000 m TVD, with a depth trend in porosity that affects the log responses.
Christian is a petrophysicist for the Snorre license, and has been with Statoil ASA since 1986. He has a MSc degree in physics from Bergen University, and has 8 years experience in special core analysis prior to petrophysics.