Petrophysical Analysis of Siliceous Ooze Sediments, Ormen Lange Field, Norway

In this paper, we interpreted logging data acquired through siliceous ooze sediments by using a new approach which allowed determination of volume fraction logs of opal and non-opal which were used with their empirical grain density to calculate grain density log. Consequently, the apparent density porosity is obtained based on the calculated grain density log and the corrected bulk density log, whereas the true density porosity is calculated by taking the number of electrons per unit volume into account. The calculated true density porosity log and the apparent density porosity log are very similar. The neutron porosity is also corrected for the hydrogen index contribution from the solid phase. The true neutron porosity is a little bit lower than the apparent neutron porosity log, but the difference is small. Our results proved to be reasonably constant. The studied intervals apparently do not contain hydrocarbons. The application of this approach clearly has great potential in obtaining reliable porosity of siliceous ooze intervals elsewhere.