Comparison and analysis of reservoir rocks and related clays

A series of instrumental and chemical analyses was made to determine the surface chemical properties of sedimentary rocks and the physical characteristics of the pores. A scanning electron microscope (SEM) with energy dispersive X-ray analytic capability was used to study the morphology of the samples, surface mineral composition and type and location of clays. A centrifuge was used to determine the pore size distributions which are correlated with the SEM observations. An inductively coupled plasma (ICP) was used to obtain complete analyses of the rocks and effluents from ion exchange tests. The ion-exchange capacity and surface area in the Berea and Cottage Grove sandstones were found to be related to the distribution of the clays in the rock matrix. Upon comparison to conventional methods the SEM was found to give quick positive results with regards to pore size, pore geometry and pore size distribution.