R. Burlot

Petrophysical properties of porous medium from Petrographic Image Analysis data

Abstract Petrographic Image Analysis (PIA) is a well-established rapid two-dimensional (2D) method to quantify pore and solid space in reservoirs and different porous materials. This paper aims to describe a method of characterization and quantification of petrophysical properties in carbonate pore systems using Petrographic Image Analysis over more than three orders of magnitude, from a submicron to a millimeter scale. We integrated two kinds of multiscaled digital image: the transmitted-light-colored petrographic images which allowed us to characterize the macroporosity; the Back-Scattered Electrons (BSE) grey level images which gave us information about microporosity. This technique enabled us to measure different classical petrophysical properties such as pore area, specific surface area, average pore diameter, distribution of pore size, pore shape factor, macroporosity and microporosity. We used image parameters in order to obtain the model of capillary pressure curve versus saturation (Pc–S). On the other hand, using empirical equations of permeability derived from Carman–Kozeny expression and a bundle of capillary tubes model, we were able to calculate the permeability of carbonate pore systems from different image parameters. The same petrophysical parameters were directly measured on core through classical three-dimensional petrophysical techniques (3D), such as Hg-injection porosimetry, permeametry and the BET technique. Finally, we compared the values different petrophysical properties of carbonate pore systems, obtained from 2D image analysis (PIA) and 3D classical petrophysical techniques.

Electrical behaviour of saturated and unsaturated geological carbonate porous systems

This chapter discusses the theoretical principles of the complex resistivity, the electrical behavior of a saturated and unsaturated porous medium, and electrofiltration phenomena. The chapter provides the physical properties of different samples. The experimental setting and the conclusions are also presented in the chapter. More than thirteen carbonate samples were investigated to measure classic electric parameters in saturated and unsaturated geological carbonate porous systems. The values of the cementation factor m range from 1.55 to 2.49. The dolomitic crystal texture shows the highest value. The electrical behavior of the carbonate porous system in an unsaturated medium is investigated from the saturation exponent n . The highest values of n are obtained for a dolomite crystal carbonate while the lowest values of n are obtained for a mudstone-wackestone texture. The values of the chargeability factor M range between 0.19 and 0.5, and they depend on the brine/gas saturation of the carbonate porous system, carbonate textures, and the salinity of brine in a porous medium.

Modelisation and circulation of fluids in geological porous systems. images analyzing and mercury porosimetry

The principal object of this article is the description and the development of a software which makes it possible to simulate in real time the circulation of a fluid in a porous rock. We obtain not only rock parameters (porosity, radius of pores connection), but we also observe the progression of the fluid in the rock (phenomenon of deflation). In the second time we explain the first results which we obtained with these simulations then we will compare these results 2D with the data 3D of porosity per mercury injection to allow us to establish a link between porosity image 2D and the data 3D.