Modified Mohr–Coulomb criterion for non-linear triaxial and polyaxial strength of intact rocks

Singh, Mahendra; Raj, Anil; Singh, B.

doi:10.1016/j.ijrmms.2011.02.004

Cited by 183 publications

(58 citation statements)

References 17 publications

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“…The stress magnitudes are often normalized to the tensile strength of intact rock [ Hancock , ; Sibson , ], and in this paper the normalized effective mean stress is referred to as the ductility index, DI (= σ ′ m / σ t ), which at the critical state can be approximated by 2 B ( B = σ c / σ t ; σ c = unconfined compressive strength), based on the models of Singh et al . [] and Barton [, ]. B is often called brittleness in the mining industry [e.g., Altindag , , ] (Figure ).…”

Section: Introductionmentioning

confidence: 99%

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Predictions of the highest potential transmissivity of fractures in fault zones from rock rheology: Preliminary results

Ishii

2015

JGR Solid Earth

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Fracture transmissivity in a fault zone is a significant parameter when solving certain geoscientific and geotechnical problems. However, the transmissivities are difficult to predict quantitatively owing to the complexity of in situ conditions such as the apertures of fractures. This study analyzes extensive data sets on flow anomalies (transmissive zones) detected from fluid/flow logs of boreholes in fault zones in the light of rock rheology, fracture mineralization/dissolution, and fracture orientation at six sites, namely Horonobe (Japan; siliceous mudstone), Wellenberg (Switzerland; argillaceous marl), Forsmark (Sweden; granite/granodiorite), Olkiluoto (Finland; gneiss), Northern Switzerland (granite/gneiss), and Sellafield (UK; volcaniclastic rocks and sandstone). The flow anomalies are correlated to fractures in fault zones. The data sets show that the transmissivities of the flow anomalies are strongly controlled by the ductility index, defined as the effective mean stress normalized to the tensile strength of the intact rock. An empirically derived power law relationship exists between the transmissivity and the ductility index, allowing predictions of the highest potential transmissivities of fractures in possible fault zones with maximum errors of about 2 orders of magnitude, due to the inevitable heterogeneity of a fault zone. The actual transmissivities may be further reduced by mineral precipitation in the fractures, or increased by mineral dissolution. Fracture orientation has no discernable influence on the transmissivity. The results may prove helpful for understanding and predicting the long-term transport properties of fault zones in the upper crust.

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Section: Introductionmentioning

confidence: 99%

“…The Mohr diagram, after Barton [, ], Ingram and Urai [], and Singh et al . []. Tensile strength = σ t ; B = σ c / σ t ; σ c = unconfined compressive strength.…”

Section: Introductionmentioning

confidence: 99%

Predictions of the highest potential transmissivity of fractures in fault zones from rock rheology: Preliminary results

Ishii

2015

JGR Solid Earth

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“…This criterion is suggested for stress conditions when three principal stresses are compressive (Singh et al, 2011) which is valid under the stress conditions of SAGD application. Oil sand formations are "locked sands" having high grain-to-grain contacts with little to no cementation (Chalaturnyk, 1996).…”

Section:   mentioning

confidence: 99%

Modifications to Butler Theory for Geomechanical Effects at the Edge of SAGD Steam Chamber. Part I: Drained Condition

Irani¹,

Gates

2013

All Days

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Steam-assisted gravity drainage (SAGD) has been demonstrated to be a successful thermal recovery technique for recovering bitumen from oil sand reservoirs where the viscosity of the bitumen is typically hundreds of thousands to millions of centipoise. High pressure and high temperature steam injection cause significant stress changes at the edge of the steam chamber including shear dilation which, in turn, can enhance the absolute permeability. The importance of considering geomechanical effects in SAGD process has been extensively discussed in the literature but geomechanical effects have been neglected in the classic SAGD analytical models. All analytical models are typically incapable of fully predicting actuall SAGD production rates without using a correction factor; this can be a result of neglecting geomechanical effects. In the research documented here, we examine geomechanical enhancement at the edge of steam chamber where the oil sand has been sheared under thermal stimulation. We describe a mechanism and evaluate the oil drainage parallel to the interface of steam chamber caused by permeability enhancement from thermal stresses. Finally, we present a modified Butler's Theory that includes geomechanical effects. The results are directly applicable to understanding the geomechanical effects on oil drainage flow at the edge of SAGD chamber.

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“…The Mohr-Coulomb failure criterion is one of the commonly accepted criteria for estimation of rock strength at a given state of stress [58,59]. Basically modified the M-C criterion by absorbing the critical state defined, and then quantifying the necessary deviation from the linear form, using a large body of experimental test data [60,61]. A similar criterion for the shear strength of rock masses, with σ c for the rock mass potentially based on the simple formula 5γQ c 1/3 (where Q c = Qσ c /100 (MPa)) [62].…”

Section: Introductionmentioning

confidence: 99%

Micromechanical Analysis of Compaction and Drilling of Granular Media- A Review

Okorie¹

2017

J Geol Geophys

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Granular matter is ubiquitous in our daily life yet far from completely understood. These granular materials have constituted a class of complex systems which exhibit global behaviors been reminiscent of solids, liquids, gases, or otherwise uniquely their own. The key to achieve good properties lies in the material structure from the molecules, via structures on nano and micro levels to the macroscopic material. This paper also reviewed selected approaches and models that have been developed for granular media prediction. However, development of new approaches at the micro and nano scales to sense the stress distribution characteristics of complex rock media, especially the grounds bearing petroleum resources of Nigeria has been of vital concern/importance to the area of petroleum drilling and exploration. By conducting such fundamental level research, development of highly efficient drilling processes with potentially much less energy inputs and minimizing the carbon blue prints is the best approach.

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Modified Mohr–Coulomb criterion for non-linear triaxial and polyaxial strength of intact rocks

Cited by 183 publications

References 17 publications

Predictions of the highest potential transmissivity of fractures in fault zones from rock rheology: Preliminary results

Predictions of the highest potential transmissivity of fractures in fault zones from rock rheology: Preliminary results

Modifications to Butler Theory for Geomechanical Effects at the Edge of SAGD Steam Chamber. Part I: Drained Condition

Micromechanical Analysis of Compaction and Drilling of Granular Media- A Review

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