METHODS USED TO CONDUCT A SEMI-QUANTITATIVE CLAY ANALYSIS OF A CLAY-RICH CRETACEOUS OIL RESERVOIR

In 2013, the Enhanced Oil Recovery Institute (EORI) participated in evaluating the Newcastle sandstone at the Bradley Unit in the Osage Field, Wyoming. The main role of EORI was to conduct clay analysis on samples collected from core in wells near the unit in order to assess the fluid-rock interaction of an Alkali/Surfactant/Polymer (ASP) EOR pilot project. Evaluation of the samples included petrographic (thin section), x-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and cation exchange capacity (CEC) analysis. Results of this analysis indicated an inverse relative abundance of Chlorite and Illite with depth, mixed layer Illite/Smectite abundance decreases with depth, the most abundant clay mineral is Kaolinite, and the CEC for this reservoir is high. These Results were then used to design a suitable ASP blend for these conditions. This project was a collaborative effort between Osage Partners LLC, TIORCO, and the Enhanced Oil Recovery Institute. The focus of this presentation is to describe the methodologies used for this analysis.