Hydraulic Fractures: Modeling and realities Brice Lecampion École Polytechnique Fédérale de Lausanne (EPFL) In this talk, we will first review the physics and mechanics of fluid driven fractures in the context of well stimulation by hydraulic fracturing. We will carefully list the different modeling “blocks” necessary to design a hydraulic fracturing treatment (in connections with the different operational steps of the process). Based on theoretical modeling and comparisons with experiments, we will also clarify a number of points raised in the literature (stability of the fracture propagation, fracture initiation, solid and fluid non-linearities, laminar vs turbulent flow, fracture height containment, etc.). We will highlight the importance of the verification of numerical models against available semi-analytical solutions (for simple fracture geometries) as well as the validation against carefully performed laboratory experiments. In a second part of the talk, we will discuss in details the multi-stage fracturing technique which consists in creating several fractures in an efficient manner along the horizontal section of a well. We will show how a combination of modeling and field observations can help in better engineering this type of operations in the context of unconventional reservoirs production. References [1] Emmanuel Detournay. Mechanics of hydraulic fractures. Annual Review of Fluid Mechanics, 48:311–339, 2016. [2] B. Lecampion and J. Desroches. Simultaneous initiation and growth of multiple radial hydraulic fractures from a horizontal wellbore. J. Mech. Phys. Sol., 82:235–258, 2015. [3] B. Lecampion, J. Desroches, R.G. Jeffrey, and A.P. Bunger. Experiments versus theory for the initiation and propagation of radial hydraulic fractures in low permeability materials. Journal of Geophysical Research: Solid Earth, 122, 2017. [4] B. Lecampion, J. Desroches, X. Weng, J. Burghardt, and E.T. Brown. Can we engineer better multistage horizontal completions? evidence of the importance of near-wellbore fracture geometry from theory, lab and field experiments. In SPE Hydraulic Fracturing Technology Conference, February 3-5 2015. SPE 173363.