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Publications on B. Lecampion

Initiation and Breakdown of an Axisymmetric Hydraulic Fracture Transverse to a Horizontal Wellbore
S. Abbas ; B. Lecampion
Book Title / Journal: Effective and Sustainable Hydraulic Fracturing - Chapter 19
Year: 2013
Mining ; Other Geotechnical
Keywords: axisymmetric hydraulic fracture ; hydraulic fracture propagation
  • Description
    • We investigate the initiation and early-stage propagation of an axi-symmetric hydraulic fracture from a wellbore drilled in the direction of the minimum principal stress in an elastic and impermeable formation. Such a configuration is akin to the case of a horizontal well and a hydraulic fracture transverse to the well axis in an open hole completion. In addition to the effect of the wellbore on the elasticity equation, the effect of the injection system compressi‐ bility is also taken into account. The formulation accounts for the strong coupling between the elasticity equation, the flow of the injected fluid within the newly created crack and the fracture propagation condition. Dimensional analysis of the problem reveals that three di‐ mensionless parameters control the entire problem: the ratio of the initial defect length over the wellbore radius, the ratio between the wellbore radius and a length-scale associated with the fluid stored by compressibility in the injection system during the well pressurization, and finally the ratio of the time-scale of transition from viscosity to toughness dominated propagation to the time-scale associated with compressibility effects. A fully coupled nu‐ merical solver is presented, and validated against solutions for a radial hydraulic fracture propagating in an infinite medium. The influence of the different parameters on the transi‐ tion from the near-wellbore to the case of a hydraulic fracture propagating in an infinite me‐ dium is fully discussed.
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The Impact of the Near-Tip Logic on the Accuracy and Convergence Rate of Hydraulic Fracture Simulators Compared to Reference Solutions
B. Lecampion ; A. Peirce ; E. Detournay ; X. Zhang ; Z. Chen ; An. Bunger ; C. DetournayC ; J. Napier ; S. Abbas ; D. Garagash ; P. Cundall
Book Title / Journal: Effective and Sustainable Hydraulic Fracturing
Year: 2013 , Series: Chapter 43
Numerical & Constitutive Modeling
Keywords: hydraulic fracture simulators ; near-tip logic
  • Description
    • We benchmark a series of simulators against available reference solutions for propagating plane-strain and radial hydraulic fractures. In particular, we focus on the accuracy and convergence of the numerical solutions in the important practical case of viscosity dominated propagation. The simulators are based on different propagation criteria: linear elastic fracture mechanics (LEFM), cohesive zone models/tensile strength criteria, and algorithms accounting for the multi-scale nature of hydraulic fracture propagation in the near-tip region. All the simulators tested here are able to capture the analytical solutions of the different configurations tested, but at vastly different computational costs. Algorithms based on the classical LEFM propagation condition require a fine mesh in order to capture viscosity dominated hydraulic fracture evolution. Cohesive zone models, which model the fracture process zone, require even finer meshes to obtain the same accuracy. By contrast, when the algorithms use the appropriate multi-scale hydraulic fracture asymptote in the near-tip region, the exact solution can be matched accurately with a very coarse mesh. The different analytical reference solutions used in this paper provide a crucial series of benchmark tests that any successful hydraulic fracturing simulator should pass.
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