Sample of Saint-Maximin limestone deformed triaxially in dry conditions at a confining pressure of 9 MPa. The distribution of Acoustic Emission hypocenters for different intervals of volumetric strain reveals compaction localization. Credit: Baud et al., 2017, Figure 10b
Source: Journal of Geophysical Research: Solid Earth

An understanding of the short- and long-term evolution of carbonate reservoirs hinges upon a fundamental understanding of inelastic compaction of porous limestone. With the development of 4D seismic monitoring, a better understanding of the in situ evolution of elastic wave velocities of porous carbonates during production or carbon dioxide injection is also clearly needed. A new set of high pressure compression experiments by Baud et al. [2017] revealed that inelastic compaction in Saint Maximin limestone was accompanied by abundant acoustic emission activity, capturing strain localization. Microstructural analysis showed grain crushing was the main mechanism of inelastic compaction in the studied limestone. Microcracking reduced P-wave velocity near the onset of inelastic compaction, while porosity reduction resulted in a significant increase in P-wave velocity.

Citation: Baud, P., Schubnel, A., Heap, M., & Rolland, A. [2017]. Inelastic compaction in high-porosity limestone monitored using acoustic emissions. Journal of Geophysical Research: Solid Earth, 122, 9989–10,008.

—André Revil, Editor, JGR: Solid Earth

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