Modeling three‐dimensional hydraulic fracture propagation using virtual multidimensional internal bonds

Huang, Kai; Zhang, Z.; Ghassemi, Ahmad

doi:10.1002/nag.2119

Cited by 48 publications

(16 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast to hydraulic fracturing in petroleum industry which involves massive high pressure injection and proppant use, some researchers argue that an EGS stimulation should be carried out at treatment pressures below the minimum principal stress and fracture self-propping by asperities is viewed as an effective means of flow rate retention (Baria et al, 1999;Cheng & Ghassemi, 2016;Evans et al, 2005;Nygren & Ghassemi, 2005;Pine & Batchelor, 1984;Rahman et al, 2002;Tester et al, 2006;Willis-Richards et al, 1996). On the other hand, the creation of new cracks could be an integral part of shear stimulation as shear slip increases the stress intensity at the tips of preexisting fractures, potentially leading to fracture propagation to generate fracture networks (Huang et al, 2013;Jung, 2013;Min et al, 2010;Ye & Ghassemi, 2018a, 2018b.…”

Section: Introductionmentioning

confidence: 99%

Injection‐Induced Shear Slip and Permeability Enhancement in Granite Fractures

2018

Self Cite

View full text Add to dashboard Cite

Shear stimulation, so‐called hydroshearing, is believed to reactivate critical or near‐critical preexisting fractures by pressurized fluid injection, causing them to slip and dilate for economic production from geothermal and unconventional petroleum reservoirs. However, little or no experiments have been conducted to directly probe the coupled hydromechanical responses and permeability evolution during fracture shearing. In this paper, we present the results of novel injection‐induced shear tests on cylindrical granite samples each containing a single tensile or saw cut fracture. The shear test on rough fractures demonstrates that retainable permeability enhancement can be achieved through dilatant shear slip. The characteristic stick‐slip behavior of the fracture during shearing is also observed. Fracture aperture controlled by effective normal stress dominates the fluid flow in stick state, while in slip state, the major contributor to production increase is the irreversible normal dilation caused by fracture shear slip. The experimental data show that depending on the fracture roughness, the fracture slip process includes two quasi‐static slip intervals with a slip velocity of ~10−9 to ~10−6 m/s and a dynamic slip interval with a slip velocity of ~10−7 to ~10−5 m/s. The fracture slip correlates well with the associated stress relaxation: a faster fracture slip induces a quicker stress relaxation, and vice versa. The influence of surface roughness on the hydromechanical responses during fracture shearing and the shear‐induced asperity degradation are also studied. The various experimental observations on rough and smooth fractures clearly indicate that the key component to shear stimulation is fracture self‐propping by asperities.

show abstract

Section: Introductionmentioning

confidence: 99%

Injection‐Induced Shear Slip and Permeability Enhancement in Granite Fractures

2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…As shown in the first column in Figure 6, the TWCs are subject to the inclination angle in Refs. [2][3][4][5][6][7][8][10][11][12]17,30,31. In a specimen with the horizontal fissure in Figure 6A, two TWCs initiate around the middle of the fissure surface; the upper TWC begins to propagate from the center-left surface of the fissure, while the lower TWC initiates from the center-right fissure surface.…”

Section: Initiation Of Tensile Wing Cracksmentioning

confidence: 99%

Morphological aspects of crack growth in rock materials with various flaws

Lee

Hong

2019

Num Anal Meth Geomechanics

View full text Add to dashboard Cite

Summary Crack evolution is initiated by the occurrence of tensile wing cracks and is then further promoted due to the crack coalescence caused by the extension of a central tensile crack segment between two relatively adjacent flaws. To understand such progressive failures in rock, a parallelized peridynamics coupled with a finite element method is utilized. Through this method, the initiation position of tensile wing cracks is observed with respect to varying inclination angles of a flaw, and then its corresponding shifting mechanism is investigated. In addition, the phenomenon of the position shifting being sensitive to various flaw shapes is discussed. Moreover, it is observed that the inclination angle of a central flaw affects the initiation position of other flaws; therefore, the initiation positions of tensile wing crack emanating from other neighboring flaws are analyzed with their angles. Following tensile wing cracks, a central tensile crack segment occurs in the bridging region between a central flaw and other neighboring flaws; the developmental patterns caused by the crack segment are discussed as well. Finally, the role a central tensile crack segment plays in the formation of crack coalescence and specimen failure is investigated in detail. The numerical results in this paper demonstrate good fidelity with established physical test results and complement them, thereby expanding the understanding of fracturing morphology in rock specimens with various flaws.

show abstract

“…A rising tide of evidence from practical treatment in the field implies that hydrofracturing cracks may initiate and grow in a complicated way that is highly affected by the complexity of in‐situ stresses and the heterogeneity of reservoir formations . Some factors play critical roles in the optimisation and evaluation of hydraulic fracturing stimulation, namely, crack types (tensile or shear), the reasons for crack nucleation, propagation, and coalescence in deep reservoirs, the effects of heterogeneous gravels, and in‐situ stresses . It is known that the initiation and growth behaviours of hydrofracturing cracks are strongly influenced by the heterogeneity of reservoir rocks such as glutenite that is found extensively in tight gas reservoirs .…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of the hydrofracturing behaviour of heterogeneous glutenite considering hydro‐mechanical coupling effects based on bonded particle models

Wang

Dong

et al. 2018

Num Anal Meth Geomechanics

View full text Add to dashboard Cite

The heterogeneity of tight reservoirs significantly influences hydrofracturing behaviours, such as crack morphology, type, initiation, propagation, and distribution. The accurate characterisation of the influencing mechanisms has become a pivotal issue in enhancing the fracturing stimulation of tight reservoirs, as well as in the prediction of tight oil and gas production. In this study, the hydrofracturing behaviours of heterogeneous glutenites and their influencing mechanisms were numerically investigated based on bonded particle models (BPMs). The geometry and mechanical properties of the natural glutenites were obtained using microfocus computed tomography (CT) and triaxial tests and were used to construct heterogeneous BPMs. The hydrofracturing behaviours of the heterogeneous BPMs under various in-situ stresses were analysed with hydro-mechanical coupling effects considered and compared with those of homogeneous BPMs under the same conditions. The numerical results show that gravels in heterogeneous glutenites inhibit crack propagation. The shear cracks that appear in the initial stage of crack development subsequently propagate and distribute around the injection hole, and there are fewer hydraulic shear cracks than tensile cracks. The crack morphologies of BPMs are found to be consistent with the experimental forms. The numerical simulation provides a way to understand the mechanisms that govern the hydrofracturing crack types and propagation of heterogeneous reservoirs.

show abstract

Modeling three‐dimensional hydraulic fracture propagation using virtual multidimensional internal bonds

Cited by 48 publications

References 22 publications

Injection‐Induced Shear Slip and Permeability Enhancement in Granite Fractures

Injection‐Induced Shear Slip and Permeability Enhancement in Granite Fractures

Morphological aspects of crack growth in rock materials with various flaws

Numerical analysis of the hydrofracturing behaviour of heterogeneous glutenite considering hydro‐mechanical coupling effects based on bonded particle models

Contact Info

Product

Resources

About