X-ray Computed Tomography Images of the Nankai Trough Seismological Experiment (NanTroSEIZE) Cores : Results From IODP Expeditions 315 and 316 and Comparison With log Density

In this paper, we present a procedure from which information contained in the 3D X-ray computed tomography (CT)images can be quantitatively extracted and transformed into very-high resolution core logs and core image logs including (1) the radial and angular distributions of density values, (2) the histogram of distribution of density and related statistical parameters, and (3) the volume, the average density and the mass contribution of voids and vugs, and the damaged and non-damaged core material fractions. In turn, these quantitative outputs (1) allow the recognition of bedding and sedimentary features, as well as natural and coring-induced fractures, (2) provide a high-resolution bulk density core log, and (3) provide quantitative estimates of core voids and core damaged zones that can further be used to characterize core quality and core disturbance. The procedure is illustrated on core data collected during IODP Expeditions 315 and 316 (Nankai Trough Seismological Experiment - Stage 1, Japan). Focusing on density estimates, XR-CT derived core bulk density is compared to Gamma-ray attenuation density measured on whole round core, moisture and density bulk density data from selected samples and LWD density log collected at similar sites during Expedition 314.