Dynamic visualization and quantification of intragranular microscopic mechanical characteristics of heterogeneous rocks via in-situ nanoindentation

Author Identifier (ORCID)

Stefan Iglauer: https://orcid.org/0000-0002-8080-1590

Abstract

We establish the first use of nanoindentation inside a scanning electron microscope (SEM; in-situ nanoindentation) to dynamically visualize and quantify intragranular microscopic mechanical characteristics in heterogeneous rocks. Microscopic mechanical properties determine macroscopic performances in various subsurface applications, including drilling, hydraulic fracturing, energy storage, and resource recovery. Conventional experimental methods provide statistical averages of mechanical properties [e.g., reduced modulus (Er) and hardness (H )] but are unable to capture relationships between local heterogeneities and their dynamic behavior under stress. Our approach enables collocated measurements which reveal significant mechanical heterogeneities across grain phases of quartz, pyrite, Nafeldspar, dolomite, and carbon within selected shale and coal samples. We directly visualize crack evolution and grain damage dynamics and link these events to abnormal variations in Erand H . This work sets a foundation for a dynamic methodology for ultrahigh-resolution investigation of the role of grain texture on mechanical properties and anomalies in complex sedimentary rock fabrics and other heterogeneous materials.

Keywords

Sedimentary rock, geologist, wellbore design, nanoindentation measurement, mineral, shale gas, complex reservoir, reservoir geomechanics, reservoir characterization, geology

Document Type

Journal Article

Date of Publication

2-1-2026

Volume

31

Issue

2

Publication Title

SPE Journal

Publisher

Society of Petroleum Engineers

School

Centre for Sustainable Energy and Resources

Funders

Natural Science Foundation of China (52125401)

Comments

Pan, B., Yin, X., Sheng, M., Huang, Z., Li, G., Kelly, S. A., Edlmann, K., Lebedev, M., Iglauer, S., & Song, X. (2026). Dynamic visualization and quantification of intragranular microscopic mechanical characteristics of heterogeneous rocks via in-situ nanoindentation. SPE Journal, 31(2), 963–974. https://doi.org/10.2118/231446-PA

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subscription content

First Page

963

Last Page

974

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Link to publisher version (DOI)

10.2118/231446-PA