Fine-grained sedimentary rocks – namely mudrocks, including their laminated fissile variety — shales – make up about two thirds of all sedimentary rocks in the Earth's crust and a quarter of the continental land mass. Additionally, organic-rich shales and mudstones are the source rocks and reservoirs for conventional and unconventional hydrocarbon resources. Mudrocks are relied upon as natural barriers for geological carbon storage and nuclear waste disposal. Consideration of mudrock multi-scale physics and multi-scale spatial and temporal behavior is vital to address emergent phenomena in shale formations perturbed by engineering activities. Unique physical characteristics of shales arise as a result of their layered and highly heterogeneous and anisotropic nature, low permeability fabric, compositional complexity, and nano-scale confined chemical environments. Barriers of lexicon among geoscientists and engineers impede the development and use of conceptual models for the coupled thermal-hydraulic-mechanical-chemical-biological (THMCB) processes in mudrock formations. This manuscript reviews the THMCB process couplings, resulting emergent behavior, and key modeling approaches. We identify future research priorities, in particular fundamental knowledge gaps in understanding the phase behavior under nano-scale confinement, coupled chemo-mechanical effects on fractures, the interplay between physical and chemical processes and their rates, and issues of non-linearity and heterogeneity. We develop recommendations for future research and integrating multi-disciplinary conceptual models for the coupled multi-scale multi-physics behavior of mudrocks. Lastly, consistent conceptual models across disciplines are essential for predicting emergent processes in the subsurface, such as self-focusing of flow, time-dependent deformation (creep), fracture network development, and wellbore stability.
Ilgen, Anastasia G., Heath, Jason E., Akkutlu, I. Yucel, Bryndzia, L. Taras, Cole, David R., Kharaka, Yousif K., Kneafsey, Timothy J., Milliken, Kitty L., Pyrak-Nolte, Laura J., & Suarez-Rivera, Roberto (2017). Shales at all scales: Exploring coupled processes in mudrocks. Earth-Science Reviews, 166(C). https://doi.org/10.1016/j.earscirev.2016.12.013
Ilgen, Anastasia G., Heath, Jason E., Akkutlu, I. Yucel, et al., "Shales at all scales: Exploring coupled processes in mudrocks," Earth-Science Reviews 166, no. C (2017), https://doi.org/10.1016/j.earscirev.2016.12.013
@article{osti_1476463,
author = {Ilgen, Anastasia G. and Heath, Jason E. and Akkutlu, I. Yucel and Bryndzia, L. Taras and Cole, David R. and Kharaka, Yousif K. and Kneafsey, Timothy J. and Milliken, Kitty L. and Pyrak-Nolte, Laura J. and Suarez-Rivera, Roberto},
title = {Shales at all scales: Exploring coupled processes in mudrocks},
annote = {Fine-grained sedimentary rocks – namely mudrocks, including their laminated fissile variety — shales – make up about two thirds of all sedimentary rocks in the Earth's crust and a quarter of the continental land mass. Additionally, organic-rich shales and mudstones are the source rocks and reservoirs for conventional and unconventional hydrocarbon resources. Mudrocks are relied upon as natural barriers for geological carbon storage and nuclear waste disposal. Consideration of mudrock multi-scale physics and multi-scale spatial and temporal behavior is vital to address emergent phenomena in shale formations perturbed by engineering activities. Unique physical characteristics of shales arise as a result of their layered and highly heterogeneous and anisotropic nature, low permeability fabric, compositional complexity, and nano-scale confined chemical environments. Barriers of lexicon among geoscientists and engineers impede the development and use of conceptual models for the coupled thermal-hydraulic-mechanical-chemical-biological (THMCB) processes in mudrock formations. This manuscript reviews the THMCB process couplings, resulting emergent behavior, and key modeling approaches. We identify future research priorities, in particular fundamental knowledge gaps in understanding the phase behavior under nano-scale confinement, coupled chemo-mechanical effects on fractures, the interplay between physical and chemical processes and their rates, and issues of non-linearity and heterogeneity. We develop recommendations for future research and integrating multi-disciplinary conceptual models for the coupled multi-scale multi-physics behavior of mudrocks. Lastly, consistent conceptual models across disciplines are essential for predicting emergent processes in the subsurface, such as self-focusing of flow, time-dependent deformation (creep), fracture network development, and wellbore stability.},
doi = {10.1016/j.earscirev.2016.12.013},
url = {https://www.osti.gov/biblio/1476463},
journal = {Earth-Science Reviews},
issn = {ISSN 0012-8252},
number = {C},
volume = {166},
place = {United States},
publisher = {Elsevier},
year = {2017},
month = {01}}
Energy Frontier Research Centers (EFRC) (United States). Center for Frontiers of Subsurface Energy Security (CFSES); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Basic Energy Sciences (BES)
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, Vol. 374, Issue 2060https://doi.org/10.1098/rsta.2015.0019