Sensitivity of shale anisotropic parameters to core cutting rotation error

doi:10.1071/EG16135

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	Sensitivity of shale anisotropic parameters to core cutting rotation error
	Guo, Shiguang 1; Verma, Sumit 2; Wang, Qing 3,4; Pang, Fei 5; Zhang, Kui 6; Sun, Haifu 7; Zhang, Xiansheng 8
刊名	EXPLORATION GEOPHYSICS
	2018-10-01
卷号	49 期号:5 页码:775-781
关键词	anisotropy cutting error delta shale TTI
ISSN号	0812-3985
DOI	10.1071/EG16135
英文摘要	In laboratories, core cannot always be cut exactly along the axis of symmetry (normal to the bedding plane), which leads to a minor core cutting rotation (CCR) error. The presence of a small CCR error can give rise to an error in computation of anisotropic parameters, which will result in erroneous P-wave and S-wave velocities (V-P, V-SV and V-SH). In this study, we test the sensitivity of Thomson's anisotropic parameters, epsilon (epsilon), gamma () and delta (), to the CCR error. In the vertical transverse isotropy (VTI) system where no rotation exists, values of epsilon, and will not vary with azimuth. Similarly, in VTI the values of V-P, V-SV and V-SH, measured at orientations with respect to the axis of symmetry, will also not vary with azimuth. We modelled and analysed the error generated, in anisotropic parameters and phase velocities, due to rotation error of 5 degrees on VTI ANNIE model data, and the Niobrara Shale core sample measurements. For these two cases, we obtained values of P-wave and S-wave velocities along with anisotropy parameters epsilon, and , at 0 degrees, 45 degrees and 90 degrees orientations with respect to the axis of symmetry, before and after a rotation of 5 degrees, for different azimuth directions. This study shows that, when the CCR error exists, epsilon, and vary with azimuth. For Niobrara Shale samples, we observed that, among all three Thomsen's parameters is the most sensitive parameter to the CCR error; when we varied azimuth, we observed a sign change of from positive to negative. For epsilon and , variation in azimuth lead to only slight changes in values without any change of sign. The CCR error affects V-P and V-s measurements the most at 45 degrees orientation, and the least at 90 degrees orientation. The maximum error occurred at 0 degrees azimuth, whereas the minimum error occurs at 90 degrees azimuth. This analysis suggests that, if core cutting rotation exists, phase velocities should be measured at 90 degrees azimuth for accurate results.
WOS研究方向	Geochemistry & Geophysics
语种	英语
出版者	CSIRO PUBLISHING
WOS记录号	WOS:000446680100016
内容类型	期刊论文
源URL	[http://ir.iggcas.ac.cn/handle/132A11/89211]
专题	地质与地球物理研究所_其他部门
通讯作者	Wang, Qing
作者单位	1.Univ Oklahoma, ConocoPhillips Sch Geol & Geophys, Norman, OK 73019 USA 2.Univ Texas Permian Basin, Dept Phys Sci, Odessa, TX 79762 USA 3.Beijing Informat Sci & Technol Univ, Sch Informat & Commun Engn, Beijing 100101, Peoples R China 4.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China 5.China Geol Survey, Ctr Oil & Gas Survey, Beijing 100029, Peoples R China 6.China Natl Petr Corp, Bureau Geophys Prospecting, Zhuozhou 072751, Hebei, Peoples R China 7.Res Inst Hengda Century Geophys Technol Co Ltd, Beijing 100020, Peoples R China 8.SINOPEC, Northwest Oilfield Branch Co, Res Inst Petr Explorat & Prod, Urumqi 830011, Xinjiang, Peoples R China
推荐引用方式 GB/T 7714	Guo, Shiguang,Verma, Sumit,Wang, Qing,et al. Sensitivity of shale anisotropic parameters to core cutting rotation error[J]. EXPLORATION GEOPHYSICS,2018,49(5):775-781.
APA	Guo, Shiguang.,Verma, Sumit.,Wang, Qing.,Pang, Fei.,Zhang, Kui.,...&Zhang, Xiansheng.(2018).Sensitivity of shale anisotropic parameters to core cutting rotation error.EXPLORATION GEOPHYSICS,49(5),775-781.
MLA	Guo, Shiguang,et al."Sensitivity of shale anisotropic parameters to core cutting rotation error".EXPLORATION GEOPHYSICS 49.5(2018):775-781.