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| Law of induced stress in multi-cluster fracturing and the effect on crack propagation |
| Received:November 02, 2016 Revised:January 30, 2017 |
| View Full Text View/Add Comment Download reader |
| DOI：10.7511/jslx20161102001 |
| KeyWord:multi-cluster fracturing complex variable function induced stresses in-situ stress analytical solutions fracture propagation XFEM |
| Author | Institution |
| 孙可明 |
辽宁工程技术大学 力学与工程学院, 阜新 |
| 张树翠 |
辽宁工程技术大学 力学与工程学院, 阜新 |
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| Abstract: |
| In order to study the induced stresses in multi-cluster cracks of horizontal wells and their effects on crack propagation,an analytical solution of 3D induced stresses considering in-situ stresses was established by double plane complex variable function conformal transformation based on 2D induced stress solutions without in-situ stress.A 3D multiple-crack propagation parametric numerical simulation was realized by Abaqus/Python and the extended finite element method.This research drew the following conclusions through analytical derivation and numerical analysis.The induced stresses beside on the crack faces have vertical compressive stress and tangential tensile stress and both are spindle shaped.The vertical induced stress influence range is about 5 times of the tangential.In contrast,the induced stresses around a crack tip have vertical tensile stress and tangential compressive stress.The induced shear stress appears beside a crack tip.The modified analytical solution of streeses after taking in-situ stress into consideration becomes lower.The induced stresses add up in multi-cluster fracturing and the combined effects get stronger along the cluster space crack.The superposed induced stresses make the crack expand and fluid pressure rise and the crack opening reduces which restricts the propogation of a single crack.The induced stress effects reduce the stress difference and change the dreictions of the minimum stresses at some positions,which can promote formation crack network. |