Caprock integrity susceptibility to permeable fracture creation

Frash, Luke P.; Carey, J. William; Ickes, Timothy Lee; Viswanathan, Hari

doi:10.1016/j.ijggc.2017.06.010

Cited by 39 publications

(49 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…To validate the model, we performed fracturing experiments using the triaxial direct‐shear methodology developed by Carey and Frash (Figure ) which allows for in situ fracturing and X‐ray imaging of rock specimens at confined stress conditions (Carey, Lei, et al, ; Frash, Carey, Lei, et al, ; Frash et al, ; Frash et al, ). Natural core‐plug specimens of anhydrite and carbonate‐rich shale were direct‐shear fractured at isotropic confining stresses ranging from 3 to 30 MPa.…”

Section: Triaxial Direct Shear Experiments Methodologymentioning

confidence: 99%

“…Properties for each material are summarized in Table . Strength properties were measured by conventional uniaxial and triaxial compression tests (ASTM D7012‐14e1, ) or by triaxial direct‐shear tests (Frash et al, ; Frash et al, ). Mineral properties were measured by X‐ray diffraction.…”

Section: Triaxial Direct Shear Experiments Methodologymentioning

confidence: 99%

“…The Marcellus shale experiments, performed first, used a second‐generation assembly modified from Carey, Lei, et al (), which included improvements enabling high‐stress confinement to 35 MPa and control of the confining pressure applied to the passive faces of the specimen. The Kevin Dome anhydrite experiments, performed second, used a third‐generation assembly modified from Frash et al (), which included improvements to further refine control of stresses on the specimen's sides and ends using nitrogen gas as the confining fluid and flexible screens instead of more rigid frits against the specimen's ends.…”

Section: Triaxial Direct Shear Experiments Methodologymentioning

confidence: 99%

“…Direct‐shear tests systemically produce nonplanar fracture roughness when rocks are fractured under constant normal stress (Carey et al, ; Frash, Carey, Lei, et al, ). The causes of this nonplanar roughness are thought to be related to complexity in the shear stress state, misalignment of the direct‐shear plane relative to the material's preferred fracturing plane, total amount of shearing displacement, and/or material heterogeneity and anisotropy (Park & Song, ; Potts et al, ; Frash et al, ). We note that these effects are also expected for in situ natural rock systems.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Scalable En Echelon Shear‐Fracture Aperture‐Roughness Mechanism: Theory, Validation, and Implications

2019

Self Cite

View full text Add to dashboard Cite

Shear fractures can facilitate fluid conductivity through rock. Aperture and roughness are controlling characteristics for a fracture's fluid conductivity. Inspired by en echelon fractures, we develop a shear "fracturelet" model that predicts anisotropic aperture with respect to the direction of shearing, rougher (nonplanar) rather than smoother (planar) fractures, and the bounds of this roughness for a coalesced fracture. This tendency for rougher fracture creation is validated by in situ X-ray images and fluid conductivity measurements from triaxial direct shear experiments on anhydrite and shale. These experiments were conducted at confining stresses from 4 to 30 MPa and shear displacement magnitudes from 0 to 2 mm on initially intact rock specimens. Hydraulic, dilatational, and local fracture apertures were measured in the experiments. Apertures exhibited strong anisotropy with more conductive flow paths forming perpendicular to the direction of shearing. Local and dilatational aperture were found to be positively correlated with increasing shear displacement but hydraulic aperture was found to vary significantly, always having values smaller than the other aperture measures at factors ranging from 0.6 to 0.0. An implication of these results is that shear fractures have a mechanism for simultaneously exhibiting very low fluid conductivity and high fluid storage volume.

show abstract

Section: Triaxial Direct Shear Experiments Methodologymentioning

confidence: 99%

Section: Triaxial Direct Shear Experiments Methodologymentioning

confidence: 99%

Section: Triaxial Direct Shear Experiments Methodologymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Scalable En Echelon Shear‐Fracture Aperture‐Roughness Mechanism: Theory, Validation, and Implications

2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…Natural rock contains a large number of natural fractures that can range in scale from sub-micron to kilometers in length [1]. A thorough understanding of crack initiation, propagation, interaction, and eventual coalescence emanating from pre-existing fractures is key to characterizing geologic risk in engineering design and to improving the safety and effectiveness of subsurface hydrologic, energy, and waste disposal activities [2][3][4]. In an effort to better understand the fracture processes within brittle solids (i.e., rock-like materials), crack coalescence has been extensively studied, both experimentally and numerically [5][6][7][8][9][10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Simulation of Fracture Coalescence in Granite via the Combined Finite–Discrete Element Method

et al. 2019

View full text Add to dashboard Cite

Fracture coalescence is a critical phenomenon for creating large fractures from smaller flaws, affecting fracture network flow and seismic energy release potential. In this paper, simulations of fracture coalescence processes in granite specimens with pre-existing cracks are performed. These simulations utilize an in-house implementation of the Combined Finite-Discrete Element method (FDEM) known as the Hybrid Optimization Software Suite (HOSS). The pre-existing cracks within the specimens follow two geometric patterns: 1) a single crack oriented at different angles with respect to the loading direction, and 2) two cracks, where one crack is oriented perpendicular to the loading direction and the other crack is oriented at different angles. The intent of this study is to demonstrate the suitability of FDEM for modeling fracture coalescence processes including: crack initiation and propagation, tensile and shear fracture behavior, and patterns of fracture coalescence. The simulations provide insight into the evolution of fracture tensile and shear fracture behavior as a function of time. The single-crack simulations accurately reproduce experimentally measured peak stresses as a function of crack inclination angle. Both the single-and double-crack simulations exhibit a linear increase in strength with increasing crack angle; the double-crack specimens are systematically weaker than the single-crack specimens.

show abstract

Hydro-mechanical measurements and x-ray imaging of sheared crystalline rock fractures from EGS Collab experiments 1 & 2

Meng¹,

Frash

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

Caprock integrity susceptibility to permeable fracture creation

Cited by 39 publications

References 36 publications

Scalable En Echelon Shear‐Fracture Aperture‐Roughness Mechanism: Theory, Validation, and Implications

Scalable En Echelon Shear‐Fracture Aperture‐Roughness Mechanism: Theory, Validation, and Implications

Simulation of Fracture Coalescence in Granite via the Combined Finite–Discrete Element Method

Hydro-mechanical measurements and x-ray imaging of sheared crystalline rock fractures from EGS Collab experiments 1 & 2

Contact Info

Product

Resources

About