Abstract We study the propagation of a fracture in an initially stressed anisotropic reservoir under shear. The focus is made on the deviation of the fracture from the principal direction due to the shearing conditions. An asymptotic model is developed, which yields the solution in terms of the effective K 2 c and the deviation angle. Then, we analyse formation of the fluid lag during propagation of a hydraulic fracture in the cases of plane and radial fracture. It is shown that there is lag between the fluid and the fract ure tip, which may be as large as half of the fracture at early stages of fracture propagation and its actual length is highly dependent on the compressibility of the reservoir rock, tectonic strength and leak-off conditions at the fracture face. In this case the speed of the fracture tip exceeds that of the fluid and is related to the length of the lag. The influence of the fluid front structure on the law of fracture propagation is studied. It is revealed that the magnitude of pressure gradient and its distribution along the fracture have a significant impact on the lag size.
Abstract In this paper the problem of redirection of a crack driven by viscous fluid under mixed mode loading is considered. The loading includes the classical Modes I - III and the hydraulically induced tangential traction on the fracture surfaces. The effect of the plastic deformation of the near tip zone is accounted for. Different criteria to determine the fracture deflection angle are examined and compared.
Abstract This study investigates the problem of a hydraulic fracture propagating in a permeable formation with an emphasis on the computation of the poroelastic stresses caused by fluid leak-off into the formation. By using the assumption of smallness of the diffusion length scale relative to the fracture size, the three-dimensional poroelastic problem around the fracture splits into two simpler problems, one involving the undrained response due to fracture opening, and another one involving one...
#1Evgenii Kanin(Skolkovo Institute of Science and Technology)H-Index: 3
#2Egor Dontsov(Skolkovo Institute of Science and Technology)H-Index: 14
Last. Andrei A. Osiptsov(Skolkovo Institute of Science and Technology)H-Index: 11
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Abstract This paper investigates the problem of a radial (or penny-shaped) hydraulic fracture propagating in a permeable reservoir. In particular, we consider the fluid exchange between the crack and ambient porous media as a pressure-dependent process. In most of the existing models, the fluid exchange process is represented as one-dimensional pressure-independent leak-off described by Carter’s law. We modify this mechanism by including the dependence of the fluid-exchange rate on the fluid pre...
#1S. K. Kanaun(Tec: Monterrey Institute of Technology and Higher Education)H-Index: 17
Abstract The problems of quasi-static poroelasticity for stationary and extending cracks in an isotropic homogeneous medium are considered. The crack driving forces are caused by pressure of fluid injected inside the crack by external sources. Using simple and double layer potentials of poroelasticity, the problems are reduced to systems of 2D-integral equations on the crack surface. The integral equations contain operators with various time-asymptotics at infinity. Neglecting operators rapidly ...
#1Qingsheng Bai(CUMT: China University of Mining and Technology)H-Index: 14
#2Zhenghe Liu(TUT: Taiyuan University of Technology)H-Index: 1
Last. Fangtian Wang(CUMT: China University of Mining and Technology)H-Index: 12
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Abstract In this study, hydromechanical hybrid finite-discrete element method (FDEM) models were employed to investigate hydraulic fracturing from oriented perforations at the microscale. Numerical calibrations were first used to obtain the microproperties that can represent the realistic behavior of sandstone. The fracture morphology and breakdown pressure obtained from the numerical hydraulic fracturing show reasonable agreements with the experimental results, indicating that the numerical res...
#1Haseeb Zia(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 7
#2Brice Lecampion(EPFL: École Polytechnique Fédérale de Lausanne)H-Index: 22
Abstract Fluid driven fractures propagate in the upper earth crust either naturally or in response to engineered fluid injections. The quantitative prediction of their evolution is critical in order to better understand their dynamics as well as to optimize their creation. We present an open-source Python implementation of a hydraulic fracture growth simulator based on the implicit level set algorithm originally developed by Peirce & Detournay (2008). This algorithm couples a finite discretizati...
#1Evgenii Kanin(Skolkovo Institute of Science and Technology)H-Index: 3
#2Dmitry I. Garagash(Skolkovo Institute of Science and Technology)H-Index: 20
Last. Andrei A. Osiptsov(Skolkovo Institute of Science and Technology)H-Index: 11
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In this paper we consider the near-tip region of a fluid-driven fracture propagating in permeable rock. We attempt to accurately resolve the coupling between the physical processes – rock breakage, fluid pressure drop in the viscous fluid flow in the fracture and fluid exchange between the fracture and the rock – that exert influence on the hydraulic fracture propagation, yet occur over length scales often too small to be efficiently captured in existing coarse grid numerical models. We consider...
#2Brice Lecampion(École nationale de l'aviation civile)H-Index: 22
Last. Haseeb Zia(École nationale de l'aviation civile)H-Index: 7
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Abstract The configuration of a hydraulic fracture (HF) propagating perpendicular to the isotropy plane of a transversely isotropic (TI) material is encountered in most sedimentary basins. We account for both elastic and fracture toughness anisotropy, and investigate fracture growth driven by the injection of a Newtonian fluid at a constant rate from a point source. In addition to the usual dimensionless parameters governing HF growth in isotropy, four dimensionless elastic parameters enter the ...
#1I. A. Garagash(Skolkovo Institute of Science and Technology)H-Index: 8
#2Andrei A. Osiptsov(Skolkovo Institute of Science and Technology)H-Index: 11
Abstract We analyze the nonuniform stress state in the vicinity of the fracture tip and its impact on apparent fracture toughness. It is shown that prescribing the boundary conditions at the deformed fracture faces allows one to take into account the effect of nonuniform tectonic stresses acting in the plane of the fracture. We conclude that the fracture may take an ellipsoidal form (aspect ratio departs from unity) as a result of interactions with anisotropic distribution of initial stresses an...
#1Dmitry I. Garagash(Skolkovo Institute of Science and Technology)H-Index: 20
Abstract Hydraulic fracture presents an interesting case of crack elasticity and fracture propagation non-linearly coupled to fluid flow. Hydraulic fracture (HF) is often modeled using the Linear Elastic Fracture Mechanics (LEFM), which assumes that the damaged zone associated with the rock breakage near the advancing fracture front is small compared to the lengthscales of other physical processes acting during propagation. The latter include dissipation in viscous fluid flow in the fracture cha...
Last. Andrei A. Osiptsov(Skolkovo Institute of Science and Technology)H-Index: 11
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We analyse the influence of fluid yield stress on propagation of a radial (penny-shaped) hydraulic fracture in a permeable reservoir. In particular, the Herschel-Bulkley rheological model is adopted that includes yield stress and non-linearity of the shear stress. The rock is assumed to be linear elastic, and the fracture is driven by the point source fluid injection with a constant volumetric rate. The fracture propagation condition follows the theory of linear elastic fracture mechanics, and C...
