Crack initiation stress of brittle rock with different porosities

Tang, Minghao; Wang, Guibin; Chen, Shiwan; Yang, Chunhe

doi:10.1007/s10064-021-02187-5

Cited by 12 publications

(2 citation statements)

References 34 publications

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“…The process of compressing rocks to the point of failure essentially occurs as cracks initiate, propagate, and coalesce [29]. The deformation damage of rocks before peak strength includes four stages: crack closure stage, elastic stage, stable crack growth stage, and unstable crack growth stage [30]. The four stage endpoints correspond to four stress thresholds, i.e., crack closure stress, crack emergence stress, crack damage stress, and peak strength [31].…”

Section: Analysis Of the Stress-strain Curve Of The Coal Rockmentioning

confidence: 99%

Three-Dimensional Heterogeneity of the Pore and Fracture Development and Acoustic Emission Response Characteristics of Coal Rocks in the Yunnan Laochang Block

Liu,

Zhang,

Xie

et al. 2024

Energies

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Studying the heterogeneity of coal reservoirs is significant to coal bed methane (CBM) exploitation. To investigate the development of the pore–fracture and acoustic emission response characteristics of the coal rock in the Yunnan Laochang block, four cores were extracted from the same coal rock in different directions. Through a comprehensive analysis using CT scanning and three-axis compression tests combined with synchronous acoustic emission experiments, a three-dimensional visualization of the pore–fracture structure and an analysis of the acoustic emission process during the elastic phase were conducted. Additionally, the impact of the heterogeneous development of pore–fractures on the acoustic emission characteristics was discussed. The results show that: there is strong heterogeneity in pore and fracture development within the coal rock, with the most significant development occurring along the direction of vertical stratification; the acoustic emission process in the elastic phase can be divided into three stages: strong–weak–strong; the development of pores and fractures affects the acoustic emission characteristics, with both counts and signal strength increasing as the percentage of voids rises; and the inferred in situ stress aligns with strike-slip faulting stress using acoustic emission. These results can provide a reference for the actual project.

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Section: Analysis Of the Stress-strain Curve Of The Coal Rockmentioning

confidence: 99%

Three-Dimensional Heterogeneity of the Pore and Fracture Development and Acoustic Emission Response Characteristics of Coal Rocks in the Yunnan Laochang Block

Liu,

Zhang,

Xie

et al. 2024

Energies

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“…From the viewpoint of rock mechanics, the stress thresholds of shale under THMC coupling, i.e., crack initiation stress (σ ci ), crack damage stress (σ cd ), and peak deviator stress (σ p ), are important factors affecting crack initiation and propagation in deep shale reservoirs during fracturing [19][20][21][22]. Most of the current studies have focused on the influence of confining pressure or bedding effects on the specific stress thresholds of shale at lower confining pressure (uniaxial or confining pressure lower than 50 MPa) [23][24][25]. However, there are few studies on the influence of the hydration effect under HTHP on the characteristic stress of reservoir rocks, although it is of great engineering importance for deep shale gas development.…”

Section: Introductionmentioning

confidence: 99%

Effect of Hydration under High Temperature and Pressure on the Stress Thresholds of Shale

Wu,

Guo,

Huang

et al. 2023

Energies

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The stress threshold of deep reservoir shale subjected to fracturing fluid immersion is an important factor affecting fracture initiation and propagation during fracturing. However, little information has been reported on the effect on shale of soaking at high temperature and high pressure (HTHP). In this study, immersion tests and triaxial compression tests were carried out at reservoir temperature and in-situ stress on the downhole cores with different mineral compositions. The characteristics of stress thresholds, i.e., crack initiation stress (σci), crack damage stress (σcd), and peak deviator stress (σp), of shale affected by the different times of soaking with low-viscosity fracturing fluid (a) and the different viscosity fracturing fluids (a, b, and c) were investigated. The results show that hydration at HTHP has a significant softening effect on the stress thresholds (σci, σcd, σp) of reservoir shale, but the softening rate varies for samples with different mineral compositions. The crack initiation stresses of quartz-rich and clay-rich shales treated with different soaking times and different soaking media remain almost unchanged in the range of 47 to 54% of the corresponding peak strength, while the crack initiation stresses of carbonate-rich shales are significantly affected. The ratio σcd/σp of quartz-rich shale is significantly affected by the different viscosity fracturing fluids (a, b) and the different times of soaking with low-viscosity fracturing fluid (a), while clay- and carbonate-rich shales are less affected. The results of this study can provide a reference for the fracturing design of deep shale gas development.

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Study on the creep properties and fracture behavior of three different rock types with a single preexisting fissure

Wang

Li³

et al. 2023

Bull Eng Geol Environ

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Crack initiation stress of brittle rock with different porosities

Cited by 12 publications

References 34 publications

Three-Dimensional Heterogeneity of the Pore and Fracture Development and Acoustic Emission Response Characteristics of Coal Rocks in the Yunnan Laochang Block

Three-Dimensional Heterogeneity of the Pore and Fracture Development and Acoustic Emission Response Characteristics of Coal Rocks in the Yunnan Laochang Block

Effect of Hydration under High Temperature and Pressure on the Stress Thresholds of Shale

Study on the creep properties and fracture behavior of three different rock types with a single preexisting fissure

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