【作者】 张伟；

【导师】 王彦春；

【作者基本信息】 中国地质大学（北京） ， 地球探测与信息技术， 2010， 博士

【摘要】 随着油气勘探程度的深入,地震勘探目标更加复杂,以叠加为基础的叠后时间偏移已经不适应成像需求。叠前时间偏移把速度分析和叠加放在共反射点道集上进行,不再受绕射波和倾斜反射波的影响,避免了共中心点道集的弥散现象,成像质量与精度得到了明显提高,已经成为复杂构造准确成像的有力工具。为了更加深入的理解叠前时间偏移算法原理、认识各种因素与成像的关系,本文主要开展了以下几方面的工作:1、对三种叠前时间偏移(克希霍夫积分法、频率—波数域法和有限差分法)原理进行了简要的介绍和评述,比较了各自优缺点和适用范围,为偏移方法的选择提供了参考。2、对叠前时间偏移成像影响因素进行了系统的研究。分别从采集因素、静校正、信噪比、分辨率、能量、速度和偏移参数等角度进行了分析和论证,指出了叠前时间偏移对数据体的敏感性、对速度场的依赖性及对偏移参数的局限性。并针对各影响因素的作用方式和特点,给出了具体的解决方案。3、对保证中间环节处理质量的监控手段和方法进行了研究,开发了成像质量监控软件PstmQc1.0,弥补处理系统中部分功能的缺陷;通过选择评价因子,设定评价标准,建立了叠前数据和偏移成果质量的综合评价机制,为把握各环节资料的品质提供了判断依据。4、结合东部某三维区块叠前时间偏移处理实例,验证研究的有效性。结果表明,立足于本研究提高成像质量的方法和监控手段,经处理得到的偏移剖面信噪比高、反射波组特征明显、断点位置清晰、绕射波归位效果好,较好地反映构造形态和地层结构,满足后续解释和反演的需求。因此,成像影响因素分析和质量监控方法的研究成果及这套叠前时间偏移的处理流程,具有一定的应用价值。叠前时间偏移是一项理论与经验紧密结合的应用技术,处理过程中每一环节均会对成像产生影响。因此,针对成像影响因素、监控方法和评价手段的研究,对于提高钻探成功率,降低勘探风险,具有十分重要的现实意义和实用价值。更多还原

【Abstract】 With the ripid development of oil and gas exploration, seismic exploration targets become more and more complex, and stack-based poststack time migration no longer meet the imaging needs. Prestack migration technology, which velocity analysis and stack are done on the common imaging point gathers, no longer subject to the impact of diffraction wave and incorrect position of the reflection wave, which avoid the diffusion phenomenon of CMP gathers, therefore, the image quality and precision has been significantly increased and has become a powerful tool for accurate imaging of complex construct. In order to further understand the migration algorithm theory, the relationship between various factors and imaging, this paper carried out the following areas:1.Three kinds of prestack time migration(Kirchhoff integral method, the frequency-wavenumber domain method and finite difference method) principle were briefly introduced and reviewed, and their application scope and merits were compared, which provided a reference for the choice of methods for the migration and application.2.Prestack time migration imaging factors were systematically studied in this paper. Respectively, the acquisition of factors, static correction, signal to noise ratio, resolution, energy, speed and migration parameters were analyzed and evidenced. This paper pointed out the sensitivity of the data body, the dependence of the velocity field and the limitations of the migration parameters for the prestack time migration. And for the mode of action of various factors and characteristics a specific solution were given.3.Quality control methods were studied in this paper. Quality control of imaging software PstmQc1.0 was developed, which make up some functions defects in the processing system. By selecting the evaluation factor, seting evaluation criteria, this paper established a comprehensive evaluation mechanisms to prestack data and outcome quality, and provided a basic judge for the data quality of each step in the procession. 4.According to a Eastern three-dimensional block prestack time migration processing instance, the validity of research were verified. The results show that using this processing and monitoring technology the migration profile have a high signal to noise ratio , obvious reflected wave group characteristics, clear breakpoint position, accurate diffraction wave homing, high purpose layer resolution, which better reflect the structure morphology and stratigraphic structure, and meet the needs of the interpretation and inversion. Thus, imaging factors analysis、quality control methods and this three-dimensional prestack time migration processing flow have obvious application value.Prestack time migration processing is an application technology of combination of theory and experience. Each stage will have an impact on migration imaging. Therefore, studying the influence factors for the imaging, monitoring methods and evaluation tools, for improving the drilling success rate and reduce exploration risk, is of great practical significance and practical value.更多还原