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Numerical study of fracture network evolution during nitrogen fracturing processes in shale reservoirs
Citation
Zhang, XX and Wang, J and Gao, F and Wang, X, Numerical study of fracture network evolution during nitrogen fracturing processes in shale reservoirs, Energies, 11, (10) Article 2503. ISSN 1996-1073 (2018) [Refereed Article]
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Copyright Statement
Copyright 2018 the authors. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) https://creativecommons.org/licenses/by/4.0/
Abstract
This paper develops a numerical model to study fracture network evolution during the nitrogen fracturing process in shale reservoirs. This model considers the differences of incompressible and compressible fluids, shear and tensile failure modes, shale heterogeneity, and the strength and permeability of both shale matrix and bedding planes through the coupling of mechanical-seepage-damage during fracturing fluid injection. The results show that nitrogen fracturing has a lower breakdown pressure and larger seepage zone than hydraulic fracturing under the same injection pressure. Tensile failure was identified as the major reason for the initiation and propagation of fractures. Ignoring the effect of bedding planes, the fracture initiation pressure, breakdown pressure, and fracturing effectiveness reached their maxima when the stress ratio is 1. Under the same strength ratio, the propagation path of the fractures was controlled by the stronger effect that was casused by the bedding angle and stress ratio. With increasing the strength ratio, the fracture number and shearing of the bedding plane increased significantly and the failure pattern changed from tensile-only mode to tensile-shear mode. These analyses indicated that the fracture network of bedding shale was typically induced by the combined impacts of stress ratio, bedding angle and strength ratio.
Item Details
Item Type: | Refereed Article |
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Keywords: | Bedding shale, fracture network, nitrogen fracturing, combined impact, failure number |
Research Division: | Engineering |
Research Group: | Mechanical engineering |
Research Field: | Solid mechanics |
Objective Division: | Energy |
Objective Group: | Mining and extraction of energy resources |
Objective Field: | Oil and gas extraction |
UTAS Author: | Zhang, XX (Mr Xiangxiang Zhang) |
UTAS Author: | Wang, X (Professor Xiaolin Wang) |
ID Code: | 128423 |
Year Published: | 2018 |
Web of Science® Times Cited: | 3 |
Deposited By: | Engineering |
Deposited On: | 2018-09-20 |
Last Modified: | 2018-11-08 |
Downloads: | 103 View Download Statistics |
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