Preliminary Investigations of Elemental Content, Microporosity, and Specific Surface Area of Porous Rocks Using PIXE and X-ray Microtomography Techniques

Abstract

Determination of physical properties of porous geological materials is of great importance for oil industry.Theknowledgeofrockspropertiesisusuallyobtainedfromporositystudiessuchasporesizedistribution,specificsurface area determination, and hydrodynamic permeability calculations. This study describes determinationof elemental composition and measurements of the particular physical properties of geological samples (poroussandstone rocks) by means of the nuclear and X-ray microprobes at the Institute of Nuclear Physics, PolishAcademyofSciencesinKrakow,Poland. Thespecialemphasishasbeenputonthecomputedmicrotomographymethod. Measurements have been carried out in close cooperation with Department of Geophysics, FGGEPAGH in Krakow, Poland. Chemical composition of the Rotliegend sandstone rock samples (few millimetersdiameter), extracted from a borehole at 2679.6 m, 2741.4 m and 2742.4 m depth have been investigated usingthe 2.2 MeV proton beam (proton induced X-ray emission technique). Next, measurements of the porosity andthe specific surface area of the pore space have been carried out using the X-ray microtomography technique.Basing on microtomographic data obtained with the high spatial resolution, simulations of the fluid dynamic inthe void space of porous media have been carried out. Lattice Boltzmann method in the 3DQ19 geometricalmodel has been used in order to predict the hydraulic permeability of the media. In order to avoid viscosity–permeabilitydependencethemultiple-relaxation-timemodelwithhalf-waybouncebackboundaryconditionshasbeenused. Computingpower-consumingprocessinghasbeenperformedwiththeuseofmoderngridinfrastructure.PACS:81.70.Tx,91.65.