ROCK POROSITY DETERMINATION BY COMBINATION OF X-RAY COMPUTERIZED-TOMOGRAPHY WITH MERCURY POROSIMETRY

First results are described of coupling of mercury porosimetry with X- ray computerized tomography (CT) as a new combination technique for ro ck porosity studies. This technique is suitable for rock samples with a pronounced mercury intrusion-extrusion hysteresis and includes CT me asurements before and after mercury intrusion. The entrapped portion o f mercury, when the pressure after the intrusion into the rock sample is reduced to 0.1 MPa, serves as a contrast agent in the porous networ k to localize spatial distribution of rock porosity by CT. The results obtained show that the mercury intrusion and therefore the porosity w ere quite different for the separate mineral phases. Therefore the com bination of mercury porosimetry and computer tomography can give 3-D d ata on mineral-specific porosity distributions with additional pore si ze information. In contrast to mercury porosimetry as a single method, results of the combination technique with CT represent a direct visua lization of porosity variation and do not depend on any special pore n etwork model.