Influence of joint anisotropy on the fracturing behavior of a sedimentary rock

Roy, Debanjan Guha; Singh, T. N.; Kodikara, Jayantha

doi:10.1016/j.enggeo.2017.08.016

Cited by 32 publications

(6 citation statements)

References 40 publications

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“…Additionally, there is a linear correlation between rock tensile strength and fracture toughness. In the fracturing process, a higher fracture toughness indicates a greater likelihood of plastic deformation, resulting in higher initiation and propagation pressures. ,,− Therefore, comprehensive analysis and evaluation of the lithological characteristics of the rock during fracturing can help optimize fracturing design and predict fracture propagation behavior, effectively improving production capacity and economic benefits.…”

Section: The Influence Of Geological Factors On Fracture Propagationmentioning

confidence: 99%

Main Control Factors of Fracture Propagation in Reservoir: A Review

Liu,

Han,

Yang

et al. 2023

ACS Omega

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The fracture distribution and internal control factors after the fracturing of unconventional oil and gas reservoirs determine the reservoir reforming effect to a large extent. Based on the research of global scholars on the influencing factors of fracture propagation, comprehensive theoretical model, and numerical simulation, this Review systematically discusses the influence of internal geological factors and external engineering factors of unconventional oil and gas reservoir on fracture propagation behavior and summarizes the current problems and development trends in fracture research. The results show the following: (1) The fracture propagation is a comprehensive process constrained by lithology and mineral composition, water saturation, nonhomogeneity, natural weak surface, and ground stress. (2) External engineering factors have a meaningful control effect on fracture propagation; the type and temperature of fracturing fluids can also change the mechanical properties of different rocks, thus affecting the fracture propagation pattern. (3) The existing fracture propagation models have certain limitations, and their computational reliability still needs to be further verified. (4) Numerical simulation can break through the limitations of physical simulation, but different simulation methods have different shortcomings and applicability. In the future, we should focus on: (1) finding parameters to quantitatively characterize heterogeneity at the 3D level, which is an important direction to study the effect of heterogeneity on fracture propagation; (2) introducing computerized methods to establish a geological model that considers multiple factors and combining it with numerical simulation software to study fracture propagation; (3) considering the characteristics of fluid–liquid–solid phase comprehensively, establishing a suitable THL coupling equation; (4) how the interaction mode of fracturing fracture is combined with the natural fracture geometry, and how the fracture is affected by fracturing engineering parameters such as fluid injection rate and viscosity of fracturing fluid; and (5) geology-engineering dynamic integration, which is an important direction to be carried out in the future.

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Section: The Influence Of Geological Factors On Fracture Propagationmentioning

confidence: 99%

Main Control Factors of Fracture Propagation in Reservoir: A Review

Liu,

Han,

Yang

et al. 2023

ACS Omega

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“…Recent studies [ 17 , 18 ] have shown that rock specimens with a larger FPZ produce more fragments, which suggests greater fracability and provides evidence supporting our hypothesis. The maximum FPZ radius has exhibited dependence on the structure [ 19 , 20 ] and loading conditions [ 21 ] of rock. Thus, we conducted experiments and numerical simulations to analyze their effects on crack tolerance and demonstrate its rationality as an evaluation index.…”

Section: Fracture Process Zone and Crack Tolerancementioning

confidence: 99%

An Evaluation Index of Fracability for Reservoir Rocks Based on Fracture Process Zone

2022

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A reliable evaluation method for the fracability (i.e., ability to generate abundant cracks) of reservoir rocks is a critical issue for maximum hydraulic fracturing efficiency. Most previous fracability indices lacked enough rationality and practicability, and thus could not consistently provide a reliable evaluation. We suggest a new fracability index called crack tolerance, which is represented by the maximum radius of the fracture process zone at the crack tip of a cracked chevron notched Brazilian disk specimen, which corresponds to the critical state for unstable propagation of the notched crack. In experiments and simulations based on the discrete element method, we showed quantitative methods to conveniently determine the value of the crack tolerance and showed that specimens with a greater crack tolerance generated more cracks before rupture and had complex morphologies, which would indicate stronger fracability. The crack tolerance can well characterize the effects of structural and loading conditions, including the grain size heterogeneity, bedding orientation, and environmental temperature, on fracability, and the inherent heterogeneity of rock is the physical basis for it as a fracability evaluation index. Our studies showed the rationality and practicability of this index and provide hints for how to produce abundant complex cracks in reservoirs.

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“…The rock pieces then glued together using an epoxy type ceramic substrate adhesive to represent the jointed tunnel model. As suggested by Roy et al [17] the adhesive was chosen such that the analogous joint behaves similarly to the actual rock joints. In the prepared jointed block, a 30 mm diameter hole is drilled through the center of the specimens.…”

Section: Specimen Preparationmentioning

confidence: 99%

Analysis and prediction of brittle failure in rock blocks having a circular tunnel under uniaxial compression using acoustic Emission technique: laboratory testing and numerical simulation

2021

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In this research, the failure mechanism and anomalous behavior of intact and jointed rock block having a circular tunnel under compression are studied. This was done by monitoring the progressive failure of a rock tunnel subjected to uniaxial loading. The tests were conducted in sandstone blocks and “Acoustic Emission” (AE) technique was used to identify the crack damage and other failure attributes. Three cases have been considered in the research, i.e. tunnel in the intact rock, with horizontal joints, and with vertical joint sets. Images of progressive failure, acoustic signals, and applied loads were simultaneously recorded during the test. The intact block demonstrates continuous crack generation while the block with horizontal joint set shows a stepwise cracking pattern. In the third case where the vertical joints were employed, the deformation was largely roof failure and joint perpendicular extension was dominant. The AE events show that a sudden drop and then a quiet period of seismic “Ib value” could be considered as the precursors to forecast the rockburst hazard. The paper also compares the results of the physical model test with a 2D finite element model. The compared results show good agreement between the physical and numerical models.

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Influence of joint anisotropy on the fracturing behavior of a sedimentary rock

Cited by 32 publications

References 40 publications

Main Control Factors of Fracture Propagation in Reservoir: A Review

Main Control Factors of Fracture Propagation in Reservoir: A Review

An Evaluation Index of Fracability for Reservoir Rocks Based on Fracture Process Zone

Analysis and prediction of brittle failure in rock blocks having a circular tunnel under uniaxial compression using acoustic Emission technique: laboratory testing and numerical simulation

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