Carbon dioxide (CO2) sequestration is one of the emerging strategies to contain anthropogenic carbon. Successful application of CO2 based Enhanced Oil recovery (EOR) techniques and its storage in unconventional reservoirs requires comprehensive understanding of CO2-fluid-rock interaction. The aim of this study is to characterize the microstructural evolution and chemo-mechanical interaction of shales with CO2 rich brine. Shale assessment, in this case, is focused on the characterization of its constituent phases such as clay, quartz or calcite. Various types of Eagle Ford shales with different compositions have been considered. First, samples are exposed to CO2-rich brine at controlled temperature and pressure conditions. Nano-indentation and Energy Dispersive X-Ray Spectrometry (EDS/EDX) are then used to quantitatively and semi-qualitatively assess the changes in phases and in mechanical properties of the rock samples. Micro-computed tomography (micro-CT) is concurrently used for analyzing the spatial distribution and textural alteration of constituents of shales after reaction. Results have revealed the existence of three regions of starkly different behaviors after CO2 exposure: a dissolution zone, a precipitation zone adjacent to the previous zone followed by a non-reacted zone. In each of these zones, phases present different mechanical properties, and their thickness and location vary with chemical composition and porosity.
|Publication status||Published - 1 Jan 2019|
|Event||53rd U.S. Rock Mechanics/Geomechanics Symposium - Brooklyn, United States|
Duration: 23 Jun 2019 → 26 Jun 2019
|Conference||53rd U.S. Rock Mechanics/Geomechanics Symposium|
|Period||23/6/19 → 26/6/19|
ASJC Scopus subject areas
- Geochemistry and Petrology