Geoffrey D. Thyne
This document reviews the various techniques to measure wettability of rocks toward oil with a focus on methodologies that may be relevant for measuring wettability in shales. The two formations of interest are the Bakken and Eagle Ford Shales. Wettability measurement techniques were developed for sandstone rocks. Shales present several basic problems when employing standard techniques because of their small grain size, low permeability and reactive components. This document contains a short review of shale oil and gas production, an overview of the relevant features of shale pore systems, and briefly summarizes the Bakken and Eagle Ford Shale properties of interest as regards wettability. A review of the current standard methodologies for measuring wettability and their limitations showed that current methods are unable to provide fast quantitative results. A new method is aloso reviewed that offers rapid measurement of wettability with semi-quantitative results that can be easily refined. This modified flotation method offers the advantages of low cost and rapid measurement of many samples over a short time. The method allows measurement of not just wettability, but also pH and associated aqueous parameters and can be performed at elevated temperature applicable to the formations of interest. The table below summarizes the important aspects of each technique.