地震勘探中建立合理的速度场是一项至关重要的工作.在地震资料解释中时深转换的准确与否取决于速度.多项式拟合得到的时深关系在单口井较为准确,对于复杂地区显得不合理.为了得到更为合理的构造图,采取了混合速度模型技术.混合速度建模技术首先加入地震处理速度体作为参考,其次利用精细解释的断层和层位建立构造框架模型作为横向约束,钻井的时深关系和地质分层数据作为纵向约束生成混合速度模型.用混合速度模型得到的深度更接近实际钻井数据,误差更小,降低了勘探风险.

涠西探区经历了始新世到渐新世应力的转变,工区内断裂复杂.受断层和地层破碎等因素的影响,现有的地震资料普遍存在同相轴的接触关系模糊、断层不够清晰等问题.为了进一步提高断层成像精度,明确断层组合关系,精细落实构造圈闭,对2套不同年代采集的2个方位的地震数据进行融合处理,实现多方位地震信息的有效融合,增加地震照明方向,改善拓宽频带范围、道集覆盖次数及速度分析精度及多次波压制及陡倾角成像效果.通过方位融合处理重点解决小断层准确归位问题,信噪比、分辨率、频带宽度以及保幅性得到提高;断面清晰、断层组合关系清楚,断裂成像质量明显改善.通过不同方位资料的融合处理,为涠西地区的下部勘探部署提供了坚实的数据基础.

This paper presents a regularization technique by incorporating the blocky geological boundary information into the Frechet derivatives matrix of the stereo-tomography inversion. Using this method, the updated velocity model can automatically exhibit a blocky feature. The geological boundary information is updated based on the updated reflector positions, which can be provided by conventional stereo-tomography itself. Compared with the conventional tomography with mixed norms or the multi-layer stereo-tomography, the presented regularization technique does not depend on a hybrid regularization terms or a hybrid velocity format. It is more straightforward and easier to implement. The synthetic data example and the field seismic data case demonstrate the robustness of this method and its inversion results are more consistent with real geological structure.

Stereo-tomography is a very attractive tomography method with which the position of reflector, the dip of the reflector and the velocity structure can be inverted simultaneously. Differed from the previous 3D stereo-tomography derived in the ray-centered coordinate, in this paper, a detailed investigation of the setup, solution and regularization of the 3D stereo-tomographic matrix equation, which is based on the ray perturbation theory in 3D Cartesian coordinate system, is presented. After this sparse and huge 3D tomographic matrix is setup, some regularization techniques have to be applied to guarantee a proper convergence. The 3D synthetic data examples demonstrate the correctness of the setup of the 3D stereo-tomographic matrix and the necessity of the related regularization techniques, from which a solid foundation for the real applications of 3D stereo-tomography is constructed.

PreviousNext No AccessBeijing 2014 International Geophysical Conference & Exposition, Beijing, China, 21-24 April 2014Preliminary practice of stereotomographyAuthors: Yao Ni*Lixin WangZhenwei LiKai YangYao Ni*Sinopec Geophysical Research Institute, Nanjing 210013, ChinaSearch for more papers by this author, Lixin WangSinopec Geophysical Research Institute, Nanjing 210013, ChinaSearch for more papers by this author, Zhenwei LiSchool of Ocean and Earth Science, Tongji University, Shanghai 200092, ChinaSearch for more papers by this author, and Kai YangSchool of Ocean and Earth Science, Tongji University, Shanghai 200092, ChinaSearch for more papers by this authorhttps://doi.org/10.1190/IGCBeijing2014-185 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract Stereotomography employs both seismic reflection traveltime and event slope to invert velocity field. With the introduction of event slope, event tracing along the whole section in prestack gather can be avoided. Also, the velocity update process of stereotomography can be more robust than reflection tomography as the multipath phenomenon of rays can be relieved greatly. We incorporate three regularization items into the inverse problem of stereotomography to strength the convergence property of inverse problem. Tests on 2D theory and real datasets show the accuracy and application potential of the proposed algorithm. Keywords: seismic, reflection, traveltime velocity, algorithmPermalink: https://doi.org/10.1190/IGCBeijing2014-185FiguresReferencesRelatedDetails Beijing 2014 International Geophysical Conference & Exposition, Beijing, China, 21-24 April 2014ISSN (online):2159-6832Copyright: 2014 Pages: 1360 publication data© 2014 Published in electronic format with permission by the Society of Exploration Geophysicists and Chinese Petroleum SocietyPublisher:Society of Exploration Geophysicists HistoryPublished Online: 24 Apr 2014 CITATION INFORMATION Yao Ni*, Lixin Wang, Zhenwei Li, and Kai Yang, (2014), "Preliminary practice of stereotomography," SEG Global Meeting Abstracts : 723-726. https://doi.org/10.1190/IGCBeijing2014-185 Plain-Language Summary Keywordsseismicreflectiontraveltime velocityalgorithmPDF DownloadLoading ...

立体层析反演方法是一种可以同时反演反射点深度、反射层局部倾角与速度结构的层析反演方法.该方法在实践中最大的特色是数据空间的分布可以是稀疏的、不连续的,因此完全克服了传统反射层析中数据空间拾取困难这一问题.该方法重新定义了层析反演的数据分量和模型分量,使得数据的提取不再需要沿着连续的层位进行.除地震波走时之外,炮、检点位置与炮、检点处射线的局部传播方向也被用来约束速度模型.将该方法应用于南海某二维深水地震数据,基于倾斜叠加能量谱对炮、检点处的局部传播方向实施交互拾取获得了可靠的立体层析数据空间,将其输入立体层析反演算法获得了可靠的偏移速度模型,证明了立体层析反演方法的稳定性和可靠性.

PreviousNext No AccessSEG Technical Program Expanded Abstracts 2012A practical approach to construct near-surface velocity structure for overthrust data based on simulated annealing algorithmAuthors: Bao-Shu ChenKai YangYu-Xiang WangZhen-Wei LiBao-Shu ChenCNOOC Research InstituteSearch for more papers by this author, Kai YangState Key Laboratory of Marine Geology, Tongji University.Search for more papers by this author, Yu-Xiang WangState Key Laboratory of Marine Geology, Tongji University.Search for more papers by this author, and Zhen-Wei LiState Key Laboratory of Marine Geology, Tongji University.Search for more papers by this authorhttps://doi.org/10.1190/segam2012-0305.1 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract The accuracy of near-surface velocity construction always plays an important role when dealing with overthrust data. Under the assumption of equivalent layered medium, we combine micro well-log information and first-arrival of surface seismic survey as prior information to estimate near-surface velocity structure based on Monte Carlo optimization scheme. The simulated annealing algorithm is taken to search the global optimum. Compared with conventional least-square (LS) based first arrival tomography, a clearer base of low-velocity-layer can be delineated thus it will surely be helpful to either wave-equation datuming or statics correction. The numerical tests on two synthetic and one real data examples demonstrated the effectiveness of this scheme. Permalink: https://doi.org/10.1190/segam2012-0305.1FiguresReferencesRelatedDetails SEG Technical Program Expanded Abstracts 2012ISSN (print):1052-3812 ISSN (online):1949-4645Copyright: 2012 Pages: 4609 Publisher:Society of Exploration Geophysicists HistoryPublished: 25 Oct 2012 CITATION INFORMATION Bao-Shu Chen, Kai Yang, Yu-Xiang Wang, and Zhen-Wei Li, (2012), "A practical approach to construct near-surface velocity structure for overthrust data based on simulated annealing algorithm," SEG Technical Program Expanded Abstracts : 1-5. https://doi.org/10.1190/segam2012-0305.1 Plain-Language Summary PDF DownloadLoading ...