CORRELATION BETWEEN MAGNETIC PROPERTIES AND PERMEABILITY: RESULTS FROM A NEW CASE STUDY IN THE NORTH SEA

摘要

A new case study on a siliciclastic North Sea shoreface reservoir has shown correlations between magnetic susceptibility,paramagnetic clay content and permeability,consistent with previous work. The previous work looked at a shoreface reservoir in a different field and utilised conventional core plugs 1 inch diameter by 1.5 inches long. The new study has undertaken magnetic measurements at two different scales: probe sensor magnetic susceptibility(on the scale of a few millimetres)for high resolution measurements on slabbed core,and coil sensor magnetic susceptibility measurements on larger 1.5 inch diameter by 3 inch long plugs. The probe and plug magnetic measurements gave very similar profiles with depth within the same cored interval. The raw magnetic susceptibility measurements from the probe and plug data picked out the main reservoir intervals very well. The processed results showed strong correlations between magnetically derived illite content and permeability. Moreover,the correlations were very similar to those in the previously studied North Sea shoreface reservoir in a different field. The results suggest there may be specific relationships between magnetic susceptibility,clay content and permeability for this type of reservoir,and validate our previous suggestions that magnetic susceptibility measurements can rapidly and non-destructively predict key petrophysical parameters(clay content,permeability)at various scales on recent or historical core samples.