Using NMR Relaxometer in the Study of Unconventional Rocks Characteristics

Abstract

Abstract NUCLEAR MAGNETIC RESONANCE (NMR), NMR RELAXOMETER, STRUCTURE OF VOID SPACE, "FRITILLARY", "WEATHERING CRUST", "BAZHENITE" (OIL SHALES), BI-MODAL NMR DISTRIBUTION, ROUTINE CAPILLARY METHODS This paper presents the results of NMR studies of structure of void space of rocks from unconventional reservoirs. Objects of the study - "fritillary", "weathering crust", "bazhenite". These rocks are difficult for studying by conventional methods due to their high heterogeneity, low porosity and permeability, presence of large amounts of clays. Therefore we have used NMR relaxometer to study the structure of void space of such rocks. We have studied more than 200 samples of the three rock types, made more than 500 NMR measurements on 100% saturated and dry samples. The nuclear magnetic resonance (NMR), accurate and non-destructive technique, was selected for these rocks,, because the standard methods for capillarity of rocks investigation (capillary pressure by porous plate and by centrifugation) do not reveal the characteristic features of the void space structure which are inherent for these rocks. These standard techniques doesn't allow to determine the pore sizes and pore channels of less than 0.1 microns, and by these methods it is impossible to study the so called "clay bound water" as a component in the fluids distribution in the rock. Same samples, were also undergone through routine core analysis measurements (permeability and porosity),, as well as detailed lithological studies using a scanning electron microscope and gas chro-matograph.