Effective porosity measurements of poorly consolidated materials using non-destructive methods

• Measurements of bulk effective porosity of poorly consolidated materials
• Natural and finely divided material having a multi-scale pore network
• Non-destructive methodology combining μCT and He-gas pycnometry
• Bulk volume of sample determined by 3D image processing

The porosity characterization of poorly consolidated sediments or soils is a key factor in understanding fluid flow and geochemical processes in surface and subsurface environments. However, porosity quantification is a challenging task due to the low cohesion of the extracted sample. In this study, we proposed and assessed a method combining X-ray computed micro-tomography (μCT) and He-gas pycnometry for the measurement of connected porosity in unconsolidated subsurface sands. The principle is based on the calculation of the total sample volume from reconstructed μCT volume and the measurement of the solid volume from He-gas pycnometry. Disaggregation of the sample may occur during handling and is taken into account by correcting the μCT volume using image processing. The measurements obtained for reference consolidated sandstone were compared with those obtained from water absorption under vacuum. The use of such non-destructive techniques offers the advantage of preserving loose sample structure. Moreover, it is a rapid and simple method that requires no sample preparation and could be easily implemented as routine analysis.