Log in

Geomechanical Properties of Thinly Interbedded Rocks Based on Micro- and Macro-Scale Measurements

  • Original Paper
  • Published:
Rock Mechanics and Rock Engineering Aims and scope Submit manuscript

Abstract

Clarifying the geomechanical properties and inherent heterogeneity of layered rocks is essential for predicting fracture morphology and designing hydraulic fracturing pum** schemes. Grid nanoindentation combined with high-resolution scanning electron microscopy and energy-dispersive spectroscopy (SEM–EDS) techniques were used to investigate mechanical differences between the sandstone layer and the mudstone layer for the downhole thinly interbedded core rocks (layered core rocks). Subsequently, the indent impressions and mechanical responses of individual minerals and multiple minerals were quantified. On this basis, the bulk mechanical properties and failure modes of the layered core rocks are investigated under confining pressures. Results indicate that quartz exhibits the highest hardness and Young’s modulus with the smallest indent impression, whereas kaolinite exhibits the opposite in each layer. When the indenter covers multiple minerals simultaneously, the mechanical responses of which are determined by the softer phases. Moreover, minerals exhibit diverse deformations and cracking patterns in different layers. Quartz shows elastic-dominated deformation in the sandstone layer, whereas medium-plastic deformation in the mudstone layer. Since the unstable sheet structures, kaolinite exhibits plastic-dominated deformation in each layer. Shear cracks and radical cracks are prone to occur in elastic-dominated minerals, while chip** damage is induced in plastic-dominated minerals. In addition, the failures of the layered core rocks tend to create along the mudstone layer since the lower mechanical properties. With the increasing of confining pressure, the compressive strength of layered core rocks gradually grows and the failure changes from tensile splitting to tensile–shear mixed failure mode and shear failure mode. The key findings of this paper can provide reliable input data for multiscale geomechanical modeling in understanding proppant embedment mechanisms and designing hydraulic fracturing treatments in coal measure strata.

Highlights

  • The mechanical responses and indent impressions of individual minerals and multiple minerals are quantified and compared in different layers.

  • Quartz shows elastic-dominated deformation in the sandstone layer, whereas medium-plastic deformation in the mudstone layer.

  • The mechanical responses of multiple minerals are determined by the softer phases and irregular indent impressions are generated.

  • The failure of the layered rocks changes from tensile splitting to shear failure with the increase of confining pressure in a macro-scale.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Subscribe and save

Springer+ Basic
EUR 32.99 /Month
  • Get 10 units per month
  • Download Article/Chapter or Ebook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime
Subscribe now

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14

Similar content being viewed by others

Data Availability Statement

The data are available from the corresponding author on reasonable request.

References

Download references

Acknowledgements

The work was supported by the Young Elite Scientists Sponsorship Program by CAST (Grant No. 2021QNRC001), National Science Fund for National R&D Program for Major Research Instruments (Grant No. 51827804), and Bei**g Natural Science Foundation (Grant No. 3222039).

Author information

Authors and Affiliations

Authors

Contributions

RC: conceptualization, methodology, analysis and writing. RY: funding acquisition, reviewing and editing. GL: experiment—supervision, investigation. ZH: resources—materials, writing—supervision. YG: visualization. MJ: data curation. ML: investigation.

Corresponding author

Correspondence to Ruiyue Yang.

Ethics declarations

Conflict of Interest

The authors declared that they have no competing interests in this paper.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Cong, R., Yang, R., Li, G. et al. Geomechanical Properties of Thinly Interbedded Rocks Based on Micro- and Macro-Scale Measurements. Rock Mech Rock Eng 56, 5657–5675 (2023). https://doi.org/10.1007/s00603-023-03360-w

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00603-023-03360-w

Keywords

Navigation