Three-dimensional poroelastic effects during hydraulic fracturing in permeable rocks

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• 作者：Saeed Salimzadeh^a ; ^b ; ^{saeeds@dtu.dk} ; Adriana Paluszny^a ; Robert W. Zimmerman^a
• 关键词：Hydraulic fractures ; Permeable rock ; Poroelasticity ; Stress intensity factors
• 刊名：International Journal of Solids and Structures
• 出版年：2017
• 出版时间：1 March 2017
• 年：2017
• 卷：108
• 期：Complete
• 页码：153-163
• 全文大小：3822 K
• 卷排序：108

文摘

A fully coupled three-dimensional finite-element model for hydraulic fractures in permeable rocks is presented, and used to investigate the ranges of applicability of the classical analytical solutions that are known to be valid in limiting cases. This model simultaneously accounts for fluid flow within the fracture and rock matrix, poroelastic deformation, propagation of the fractures, and fluid leakage into the rock formation. The model is validated against available asymptotic analytical solutions for penny-shaped fractures, in the viscosity-dominated, toughness-dominated, storage-dominated, and leakoff-dominated regimes. However, for intermediate regimes, these analytical solutions cannot be used to predict the key hydraulic fracturing variables, i.e. injection pressure, fracture aperture, and length. For leakoff-dominated cases in permeable rocks, the asymptotic solutions fail to accurately predict the lower-bound for fracture radius and apertures, and the upper-bound for fracture pressure. This is due to the poroelastic effects in the dilated rock matrix, as well as due to the multi-dimensional flow within matrix, which in many simulation codes is idealised as being one-dimensional, normal to the fracture plane.