Response of Velocity Anisotropy of Shale Under Isotropic and Anisotropic Stress Fields

doi:10.1007/s00603-017-1356-2

CORC > 武汉岩土力学研究所 > 中科院武汉岩土力学所 > 岩土力学所知识全产出 > 期刊论文

	Response of Velocity Anisotropy of Shale Under Isotropic and Anisotropic Stress Fields
	Li, Xiaying 1,2,3; Lei, Xinglin 3; Li, Qi1,2
刊名	ROCK MECHANICS AND ROCK ENGINEERING
	2018
卷号	51 期号:3 页码:695-711
关键词	Shale Velocity anisotropy Anisotropic stress Anisotropy reversal Transverse isotropy Longmaxi formation
ISSN号	0723-2632
DOI	10.1007/s00603-017-1356-2
英文摘要	We investigated the responses of P-wave velocity and associated anisotropy in terms of Thomsen's parameters to isotropic and anisotropic stress fields on Longmaxi shales cored along different directions. An array of piezoelectric ceramic transducers allows us to measure P-wave velocities along numerous different propagation directions. Anisotropic parameters, including the P-wave velocity alpha along a symmetry axis, Thomsen's parameters epsilon and delta, and the orientation of the symmetry axis, could then be extracted by fitting Thomsen's weak anisotropy model to the experimental data. The results indicate that Longmaxi shale displays weakly intrinsic velocity anisotropy with Thomsen's parameters epsilon and delta being approximately 0.05 and 0.15, respectively. The isotropic stress field has only a slight effect on velocity and associated anisotropy in terms of Thomsen's parameters. In contrast, both the magnitude and orientation of the anisotropic stress field with respect to the shale fabric are important in controlling the evolution of velocity and associated anisotropy in a changing stress field. For shale with bedding-parallel loading, velocity anisotropy is enhanced because velocities with smaller angles relative to the maximum stress increase significantly during the entire loading process, whereas those with larger angles increase slightly before the yield stress and afterwards decrease with the increasing differential stress. For shale with bedding-normal loading, anisotropy reversal is observed, and the anisotropy is progressively modified by the applied differential stress. Before reaching the yield stress, velocities with smaller angles relative to the maximum stress increase more significantly and even exceed the level of those with larger angles. After reaching the yield stress, velocities with larger angles decrease more significantly. Microstructural features such as the closure and generation of microcracks can explain the modification of the velocity anisotropy due to the applied stress anisotropy.
WOS研究方向	Engineering ; Geology
语种	英语
出版者	SPRINGER WIEN
WOS记录号	WOS:000426760700003
内容类型	期刊论文
源URL	[http://119.78.100.198/handle/2S6PX9GI/4239]
专题	岩土力学所知识全产出_期刊论文国家重点实验室知识产出_期刊论文
作者单位	1.Univ Chinese Acad Sci ; 2.Chinese Acad Sci, Inst Rock & Soil Mech, State Key Lab Geomech & Geotech Engn ; 3.Natl Inst Adv Ind Sci & Technol
推荐引用方式 GB/T 7714	Li, Xiaying,Lei, Xinglin,Li, Qi. Response of Velocity Anisotropy of Shale Under Isotropic and Anisotropic Stress Fields[J]. ROCK MECHANICS AND ROCK ENGINEERING,2018,51(3):695-711.
APA	Li, Xiaying,Lei, Xinglin,&Li, Qi.(2018).Response of Velocity Anisotropy of Shale Under Isotropic and Anisotropic Stress Fields.ROCK MECHANICS AND ROCK ENGINEERING,51(3),695-711.
MLA	Li, Xiaying,et al."Response of Velocity Anisotropy of Shale Under Isotropic and Anisotropic Stress Fields".ROCK MECHANICS AND ROCK ENGINEERING 51.3(2018):695-711.