A rock brittleness evaluation method in interbedded reservoirs based on statistical damage constitutive

Abstract The significant heterogeneity of sandstone and mudstone interbedded reservoirs complicates the accurate evaluation of formation brittleness, thereby affecting the optimization of fracturing stage design. This paper first derives a statistical damage constitutive model to predict rock stress...

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Main Authors: Zhuang Liu, Tingen Fan, Zongjun Wang, Renfeng Yang, Hongjun Fan, Haifeng Wang, Nachuan Hu
Format: Article
Language:English
Published: SpringerOpen 2025-06-01
Series:Journal of Petroleum Exploration and Production Technology
Subjects:
Online Access:https://doi.org/10.1007/s13202-025-02008-5
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author Zhuang Liu
Tingen Fan
Zongjun Wang
Renfeng Yang
Hongjun Fan
Haifeng Wang
Nachuan Hu
author_facet Zhuang Liu
Tingen Fan
Zongjun Wang
Renfeng Yang
Hongjun Fan
Haifeng Wang
Nachuan Hu
author_sort Zhuang Liu
collection DOAJ
description Abstract The significant heterogeneity of sandstone and mudstone interbedded reservoirs complicates the accurate evaluation of formation brittleness, thereby affecting the optimization of fracturing stage design. This paper first derives a statistical damage constitutive model to predict rock stress-strain curves under in-situ conditions, and the application of the model has been validated by experimental results. It then develops an energy-based brittleness evaluation procedure that accounts for the effects of lithology, physical properties and in-situ conditions on rock brittleness at a logging scale. The results indicate that highly brittle rocks can store significant elastic energy during loading and release it abruptly without requiring additional energy input. Rocks with a low Young’s modulus can exhibit high brittleness, as the post-peak mechanical behavior of rock controls its overall brittleness. As confining pressure increases, the brittleness of rocks decreases, rocks with the same Young’s modulus exhibits a 44.4% increase in brittleness when confining pressure decreases by 20 MPa. The newly proposed method effectively evaluates the reservoir energy-based brittleness index at the logging scale. This evaluation method is more sensitive to strongly heterogeneous formations and is more objective considering the cumulative impact of internal and external conditions without biased energy weighting.
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issn 2190-0558
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publishDate 2025-06-01
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series Journal of Petroleum Exploration and Production Technology
spelling doaj-art-2c79c64bc2924c8da2e7db91fb5489fb2025-08-20T03:04:17ZengSpringerOpenJournal of Petroleum Exploration and Production Technology2190-05582190-05662025-06-0115711210.1007/s13202-025-02008-5A rock brittleness evaluation method in interbedded reservoirs based on statistical damage constitutiveZhuang Liu0Tingen Fan1Zongjun Wang2Renfeng Yang3Hongjun Fan4Haifeng Wang5Nachuan Hu6CNOOC Research Institute Ltd.CNOOC Research Institute Ltd.CNOOC Research Institute Ltd.CNOOC Research Institute Ltd.CNOOC Research Institute Ltd.CNOOC Research Institute Ltd.CNOOC Research Institute Ltd.Abstract The significant heterogeneity of sandstone and mudstone interbedded reservoirs complicates the accurate evaluation of formation brittleness, thereby affecting the optimization of fracturing stage design. This paper first derives a statistical damage constitutive model to predict rock stress-strain curves under in-situ conditions, and the application of the model has been validated by experimental results. It then develops an energy-based brittleness evaluation procedure that accounts for the effects of lithology, physical properties and in-situ conditions on rock brittleness at a logging scale. The results indicate that highly brittle rocks can store significant elastic energy during loading and release it abruptly without requiring additional energy input. Rocks with a low Young’s modulus can exhibit high brittleness, as the post-peak mechanical behavior of rock controls its overall brittleness. As confining pressure increases, the brittleness of rocks decreases, rocks with the same Young’s modulus exhibits a 44.4% increase in brittleness when confining pressure decreases by 20 MPa. The newly proposed method effectively evaluates the reservoir energy-based brittleness index at the logging scale. This evaluation method is more sensitive to strongly heterogeneous formations and is more objective considering the cumulative impact of internal and external conditions without biased energy weighting.https://doi.org/10.1007/s13202-025-02008-5Brittleness evaluationEnergy evolutionDamage constitutiveInterbedded reservoirRock mechanicsIn-situ conditions
spellingShingle Zhuang Liu
Tingen Fan
Zongjun Wang
Renfeng Yang
Hongjun Fan
Haifeng Wang
Nachuan Hu
A rock brittleness evaluation method in interbedded reservoirs based on statistical damage constitutive
Journal of Petroleum Exploration and Production Technology
Brittleness evaluation
Energy evolution
Damage constitutive
Interbedded reservoir
Rock mechanics
In-situ conditions
title A rock brittleness evaluation method in interbedded reservoirs based on statistical damage constitutive
title_full A rock brittleness evaluation method in interbedded reservoirs based on statistical damage constitutive
title_fullStr A rock brittleness evaluation method in interbedded reservoirs based on statistical damage constitutive
title_full_unstemmed A rock brittleness evaluation method in interbedded reservoirs based on statistical damage constitutive
title_short A rock brittleness evaluation method in interbedded reservoirs based on statistical damage constitutive
title_sort rock brittleness evaluation method in interbedded reservoirs based on statistical damage constitutive
topic Brittleness evaluation
Energy evolution
Damage constitutive
Interbedded reservoir
Rock mechanics
In-situ conditions
url https://doi.org/10.1007/s13202-025-02008-5
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