Planar hydraulic fracture growth perpendicular to the isotropy plane in a transversely isotropic material

Moukhtari, Fatima-Ezzahra; Lecampion, Brice; Zia, Haseeb

doi:10.1016/j.jmps.2020.103878

Cited by 28 publications

(34 citation statements)

References 35 publications

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“…The problem of a growing hydraulic fracture in an anisotropic rock is outside the scope of the present study; however, an approximate mitigation can be proposed based on the approximate solutions available in the literature. The shape of a hydraulic fracture in a transversely isotropic material such as shales resembles an ellipse where the ellipse aspect ratio may be approximated from (Moukhtari et al, 2020)…”

Section: 1029/2020gl087563mentioning

confidence: 99%

“…Lateral propagation of a hydraulic fracture can also be a result of anisotropy in material properties including elastic stiffness and fracture toughness. In shales, for instance, fractures are elongated in horizontal direction (Fisher & Warpinski, 2012; Fu et al, 2019; Moukhtari et al, 2020). The problem of a growing hydraulic fracture in an anisotropic rock is outside the scope of the present study; however, an approximate mitigation can be proposed based on the approximate solutions available in the literature.…”

Section: Lateral Extension Of Gravity‐driven Fracturesmentioning

confidence: 99%

\frac{b}{a} = {(\frac{K_{italicIc, 1} E_{3}'}{K_{italicIc, 3} E_{1}'})}^{2} = {(\frac{κ}{β})}^{2}

where, K Ic ,1 and K Ic ,3 are fracture toughness in horizontal and vertical directions, respectively; E 1 ′ and E 3 ′ are the plane‐strain moduli in horizontal and vertical directions, respectively; κ = K Ic ,1 / K Ic ,3 and β = E 1 ′/ E 3 ′. As a compensation for the smaller size of the hydraulic fracture in the vertical direction (compared to the reference circular shape used in this study), we suggest that the minimum radius of hydraulic fracture given in Equation to be increased by a factor that depends on the mechanical anisotropy ratio ( β /κ).…”

Section: Lateral Extension Of Gravity‐driven Fracturesmentioning

confidence: 99%

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Gravity Hydraulic Fracturing: A Method to Create Self‐Driven Fractures

Salimzadeh

Zimmerman

Khalili

2020

Geophysical Research Letters

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In this study, we investigate the possibility of using a high-density fluid to induce downward fracture growth in a hydraulic fracturing process. We propose a mathematical model to calculate the minimum amount of a dense fluid required to trigger downward fracture propagation under gravity forces, and we verify the calculated minimum volume of the fluid through numerical simulations. Results show that when the injected fluid exceeds the minimum amount, a steady downward growth of the hydraulic fracture is obtained. The fracture propagation consists of two distinct responses: The first response can occur under either toughness-dominated, viscosity-dominated, or an intermediate hydraulic fracturing regime, depending on fluid rheology, rock properties, and injection scenario. The second response occurs mainly under the toughness-dominated regime, meaning the predominant energy dissipation mechanism is to overcome the fracture toughness and break the rock. In the latter, the speed of the downward fracture growth depends on the viscosity and fluid weight.

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Section: 1029/2020gl087563mentioning

confidence: 99%

Section: Lateral Extension Of Gravity‐driven Fracturesmentioning

confidence: 99%

\frac{b}{a} = {(\frac{K_{italicIc, 1} E_{3}'}{K_{italicIc, 3} E_{1}'})}^{2} = {(\frac{κ}{β})}^{2}

Section: Lateral Extension Of Gravity‐driven Fracturesmentioning

confidence: 99%

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Gravity Hydraulic Fracturing: A Method to Create Self‐Driven Fractures

Salimzadeh

Zimmerman

Khalili

2020

Geophysical Research Letters

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“…At early injection times, the fracturing fluid movement controls the fracture propagation process, dominated by the fluid viscosity. On the other hand, the toughness regime dominates at large injection times when the effect of the fracture energy becomes larger than the viscous fluid dissipation 6 . It is important to mention here, also, that between these limiting regimes there is a transition zone during the process, with some peculiarities and effects on the hydraulic fracture propagation 5 .…”

Section: Introductionmentioning

confidence: 97%

“…Most of the work done so far by other authors resolve the hydraulic fracture propagation assuming an isotropic rock matrix or simplifying unconventional shale rocks as homogeneous anisotropic 5,6 . However, most shale rocks display certain degree of elastic anisotropy, with the elastic modulus in the horizontal direction, aligned to the shales bedding planes, generally greater than in the vertical direction (see e.g., 30 ).…”

Section: Introductionmentioning

confidence: 99%

Hydraulic fracture propagation barriers induced by weak interfaces in anisotropic rocks

Celleri¹,

Sánchez²

2021

Num Anal Meth Geomechanics

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In the Oil&Gas industry, hydraulic fracturing is a technique that makes unconventional reservoirs economically viable. Despite the high impact of the stimulation processes on the productivity of the wells, hydraulic fractures are modeled assuming vertical and planar propagation in most cases. In Argentina, Vaca Muerta formation is the most important unconventional reservoir. It is predominately in a strike‐slip stress regime with areas in thrust regime, and has also strong elastic anisotropy with widely spread sub‐horizontal mechanical discontinuities such as calcitic veins or ash beds, that could act as preferential propagation paths. The effect of these heterogeneities on the fracture propagation, typically underestimated, is a key issue to model the hydraulic fracture geometry, to estimate the stimulated volume, and to optimize production under these complex mechanical conditions. In this work, we use a coupled fluid ‐ rock mechanics model that accounts for elastic anisotropy and weak discontinuities to study the fracture height growth. Fracture initiation and propagation are modeled using a Discontinuous Galerkin (DG) finite elements formulation with a softening Cohesive Zone Model (CZM). We analyze Vaca Muerta formation representative mechanical properties and provide some fundamentals on typical field problems like vertical containment induced by lamination and layering or horizontal fracture propagation with their consequent loss of productivity. We find, for typical Vaca Muerta formation conditions, that not only the weak bedding strength controls the height propagation of the hydraulic fracture but also the degree of anisotropy plays an important role under harsh stress regimes and high heterogeneity of the formation.

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