Assessment of Tight Rock Wettability by Spontaneous Imbibition at Elevated Pressures

Date
2019-01-23
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Abstract
Wettability is an important reservoir property and must be well-understood as it gives an indication of how fluids are distributed through the porous media. In tight reservoirs, which generally have been produced using hydraulic fracturing, the wettability evaluation becomes even more important for enhancing oil recovery, as it is a reference point for understanding the interaction between the fracturing fluids and the reservoir, to then be able to alter the rock wettability tendency into a more water-wet system by using appropriate fracturing fluids that would displace the oil into the matrix to the fractures by spontaneous imbibition. It is known that the wettability evaluation of a reservoir is affected by multiple factors (core preservation state, fluid properties, temperature and pressure), and that the most representative results are obtained by using conditions as similar to the reservoir as possible. However, different than conventional reservoirs, in tight media reservoirs the measurement of wettability and its alteration become even more challenging, basically due to its low porosity and permeability, and also due to its mineralogical heterogeneity. As a first approach for evaluating the wettability tendency of tight media reservoirs as close as possible to the reservoir conditions, a novel apparatus and methodology were designed in this thesis for assessing the wettability tendency of tight media samples by spontaneous imbibition tests at elevated pressures. Furthermore, the wettability tendency of four tight media core plugs from the Lower Shaunavon reservoir were evaluated by multiple spontaneous imbibition tests at atmospheric and elevated pressures.
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Keywords
Wettability, tight media reservoirs, spontaneous imbibition
Citation
Sánchez Martinez, J. J. (2019). Assessment of Tight Rock Wettability by Spontaneous Imbibition at Elevated Pressures (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.