Influence of the microstructure on stress-dependent P-wave anisotropy in sandstone

doi:10.1093/gji/ggab383

	Influence of the microstructure on stress-dependent P-wave anisotropy in sandstone
	Shen, Haimeng 1,2; Li, Xiaying 1,2; Li, Qi 1,2
刊名	GEOPHYSICAL JOURNAL INTERNATIONAL
	2022-02-01
卷号	228 期号:2 页码:876-892
关键词	Microstructure Geomechanics Numerical modelling Acoustic properties Wave propagation
ISSN号	0956-540X
DOI	10.1093/gji/ggab383
英文摘要	To understand the factors that affect the stress-dependent P-wave velocity anisotropy, a method is proposed to simulate anisotropic microcracks and minerals based on the discrete element method (DEM). Laboratory triaxial tests and numerical simulations were performed on sandstone samples with bedding orientations parallel and perpendicular to the maximum principal stress. The ellipse fitting method was applied to analyse the variation in P-wave anisotropy. The micromechanism of stress-dependent P-wave anisotropy was revealed. The evolution of microcracks is the main reason for the change in P-wave anisotropy under compression. As the confining pressure increases, the magnitude of the P-wave anisotropy is reduced. The weakening of the P-wave anisotropy results from the decrease in the number of open microcracks. Under deviatoric stress loading, the P-wave anisotropy of the bedding-parallel sample in the axial direction is strengthened. Anisotropy reversal occurs in the bedding-normal sample. The microcrack behaviour depends on the direction of maximum principal stress. The variation in microcrack anisotropy induced by stress controls the evolution of P-wave velocity anisotropy. The stress at which anisotropic reversal occurs depends on the preferred orientation mineral. The DEM model offers the unique ability to directly examine the variation in microstructure anisotropy that causes the change in P-wave anisotropy.
资助项目	National Natural Science Foundation of China[41902297] ; National Natural Science Foundation of China[41872210] ; Natural Science Foundation of Hubei Province[2018CFB292] ; Open Research Fund of the State Key Laboratory of Geomechanics and Geotechnical Engineering[Z017006] ; China Scholarship Council[202004910626]
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	OXFORD UNIV PRESS
WOS记录号	WOS:000741354200011
内容类型	期刊论文
源URL	[http://119.78.100.198/handle/2S6PX9GI/30774]
专题	中科院武汉岩土力学所
通讯作者	Li, Qi
作者单位	1.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 2.Chinese Acad Sci, Inst Rock & Soil Mech, State Key Lab Geomech & Geotech Engn, Wuhan 430071, Peoples R China
推荐引用方式 GB/T 7714	Shen, Haimeng,Li, Xiaying,Li, Qi. Influence of the microstructure on stress-dependent P-wave anisotropy in sandstone[J]. GEOPHYSICAL JOURNAL INTERNATIONAL,2022,228(2):876-892.
APA	Shen, Haimeng,Li, Xiaying,&Li, Qi.(2022).Influence of the microstructure on stress-dependent P-wave anisotropy in sandstone.GEOPHYSICAL JOURNAL INTERNATIONAL,228(2),876-892.
MLA	Shen, Haimeng,et al."Influence of the microstructure on stress-dependent P-wave anisotropy in sandstone".GEOPHYSICAL JOURNAL INTERNATIONAL 228.2(2022):876-892.