Title

Beam tomography based on transmission traveltime

单位

(1.波现象与智能反演成像研究组(WPI),同济大学海洋与地球科学学院,上海200092;2.中石化石油工程地球物理公司国际业务发展中心,江苏南京210000;3.中国石油化工股份有限公司中原油田分公司物探研究院,河南濮阳457000)

Organization

(1.Wave Phenomena and Intelligent Inversion Imaging Group (WPI),School of Ocean and Earth Science,Tongji University,Shanghai 200092,China;2.International Business Development Center,SINOPEC Geophysical Corporation,Nanjing 210000,China;3.Institute of Geophysical Exploration,Zhongyuan Oilfield Branch,SINOPEC,Puyang 457000,China)

摘要

无论是高精度的构造成像,还是高保真的针对岩性油藏的成像,都越来越依赖于有一个准确的浅中层速度模型(含各向异性和Q值参数模型)。随着“两宽一高”地震数据采集技术的进步,透射波相较于反射波信噪比更高,参数反演更自动化,因此利用透射波信息进行浅中层参数估计得到了特别的重视。首先从层析成像的理论框架出发,系统地论述了波动方程层析、波束层析以及射线层析的异同,剖析了参数迭代公式中各项的含义,认为层析正问题、地震数据的预条件以及模型的正则化是利用透射波旅行时层析成像方法挖掘“两宽一高”地震数据信息时应注意的几个核心问题。然后,重点介绍了加权地震走时的含义及其基于瞬时走时信息的自动化拾取策略。最后,简述了Beam束层析成像算法理论及其对观测系统的适应性,提出了MPI+OpenMP的策略缓解海量地震数据带来的存储与计算压力。海上实际地震资料的处理结果说明了透射波旅行时Beam层析处理流程在“两宽一高”地震数据处理中的可行性。

Abstract

Abstract: Both high-precision structural imaging and high-fidelity imaging of lithologic reservoirs rely on an accurate model of shallow and middle velocities that accounts for the medium anisotropy and its Q parameter.With the development of the technology for the acquisition of broadband,wide-azimuth,and high-density (BWH) seismic data,the parameter inversion for the transmitted wave has become more automatic thanks to the higher SNR compared to that of the reflected wave.Therefore,it has become convenient to rely on transmitted wave data for the parameter estimation of the shallow-middle velocity model.Within the theoretical framework of the tomography,this paper first presents a discussion on the similarities and differences among wave equation tomography,beam tomography and ray tomography,and analyzes the meaning of each parameter involved in the iterative formula.Subsequently,the forward problem of tomography,data preconditioning,and model regularization are identified as key problems affecting the results of the tomography based on transmission travel time using BWH seismic data.The meaning of the weighted seismic travel time is then explained,and an automatic pick-up strategy is presented,which is based on instantaneous travel time information.Finally,the theory of the beam tomography algorithm and how the algorithm adapts to the observations are briefly described,and an MPI+OpenMP strategy is proposed to alleviate the storage and computational burden required by the large amount of seismic data handled by the algorithm.A test carried out on marine data showed the feasibility for practical application of the beam tomography based on transmission travel time.

关键词：

两宽一高; Bayes理论; 透射波; 瞬时旅行时; Beam束; 数据预条件; 模型正则化; 层析反演;

Keywords:

'broadband,wide-azimuth and high-density seismic’ data,; Bayesian theory,; transmitted wave,; instantaneous traveltime,; Beam,; data preconditions,; model regularization,; tomography inversion;

基金项目

国家自然科学基金(41774126)和国家科技重大专项(2016ZX05024-001,2016ZX05006-002)共同资助。

DOI

10.3969/j.issn.1000-1441.2019.03.005

透射波旅行时Beam层析成像方法