叠前时间偏移高精度成像应用研究

发布时间：2018-01-28 13:31

本文关键词： 叠前时间偏移高精度成像偏移速度偏移孔径最大倾角　出处：《中国地质大学(北京)》2015年硕士论文　论文类型：学位论文

【摘要】：随着现代地震勘探难度的加大,所面临的地质条件越来越困难,区域构造越来越复杂,对地震成像精度的要求越来越高。叠前时间偏移作为地震偏移成像的主导技术,已成为解决复杂构造地区地震资料成像问题的首要选择。因此,叠前时间偏移的成像精度研究有其实际意义。研究区原始资料信噪比低,品质差,老剖面成像精度低,波组特征模糊,偏移归位不准确。因此,提出研究思路如下:在采用高精度的噪声压制技术提高资料信噪比的前提下,(1)对叠前时间偏移的关键参数——速度进行优化分析;(2)研究偏移孔径、偏移的最大倾角等其他参数的影响。本文首先介绍廊固凹陷柳河营地区的工区概况及资料情况;其次对比研究两大类叠前时间偏移的方法原理,对其特点进行深入探讨,选定克希霍夫积分法作为叠前时间偏移高精度成像研究的理论基础;再次以高质量的CMP道集为基础数据,进行叠前时间偏移速度参数的优化分析;然后分析其他参数对成像精度的影响;最后进行处理效果分析。通过对廊固凹陷柳河营地区叠前时间偏移高精度成像的研究,发现:(1)高信噪比的炮集数据是提高叠前时间偏移成像精度的基础;(2)由于以叠加速度为初始偏移速度需要地下介质是水平层状介质的前提,而DMO速度适用于地下岩层有一定倾角的情况,且DMO速度作为初始偏移速度时得到的叠前时间偏移剖面成像精度更高。因此,DMO速度更适合作为初始偏移速度,在进行叠前时间偏移处理之前应做好DMO工作;(3)在偏移速度的优化分析过程中,用测井资料中的P-Sonic曲线来监控偏移速度的趋势,能够更高效的建立准确的偏移速度场;(4)除偏移速度外,偏移孔径和偏移的最大倾角也是Kirchhoff叠前时间偏移的重要参数。高精度的叠前时间偏移处理流程应用于廊固凹陷柳河营地区,成像精度得到提高,波组特征清晰,偏移归位准确,断点位置可靠,构造形态突出。因此,本文的研究方法是切实可行的,确实可以提高成像精度。
[Abstract]:With the increasing difficulty of modern seismic exploration, the geological conditions are becoming more and more difficult, and the regional structure is becoming more and more complex. Prestack time migration, as the dominant technology of seismic migration imaging, has become the first choice to solve the problem of seismic imaging in complex structural areas. The study of imaging accuracy of prestack time migration has its practical significance. The original data in the study area have low signal-to-noise ratio (SNR), poor quality, low imaging accuracy of old section, fuzzy wave group characteristics and inaccurate migration and homing. The research ideas are as follows: on the premise of using high precision noise suppression technology to improve the signal to noise ratio of data, the paper optimizes and analyzes the key parameter of prestack time migration-velocity; (2) study the influence of migration aperture, maximum inclination angle and other parameters. Firstly, this paper introduces the general situation and data of Liuheying area in Langgu depression; Secondly, the principle and characteristics of two kinds of prestack time migration are studied, and the Kirchhoff integration method is selected as the theoretical basis of high precision imaging research of prestack time migration. Thirdly, based on the high quality CMP gathers, the prestack time migration velocity parameters are optimized and analyzed. Then the influence of other parameters on imaging accuracy is analyzed. Finally, the processing effect is analyzed. By studying the high-precision imaging of prestack time migration in Liuheying area of Langgu depression, it is found that the prestack time migration with high SNR is the basis of improving the imaging accuracy of prestack time migration. 2) because the stack velocity is the initial migration velocity, the underground medium is the premise of the horizontal layered medium, and the DMO velocity is suitable for the case where the underground rock has a certain dip angle. And the prestack time migration profile with DMO velocity as the initial migration velocity has higher imaging accuracy, so the DMO velocity is more suitable as the initial migration velocity. DMO should be done well before prestack time migration. 3) in the process of optimization analysis of migration velocity, the P-Sonic curve in logging data can be used to monitor the trend of migration velocity, and the accurate migration velocity field can be established more efficiently. In addition to the migration velocity. The migration aperture and the maximum dip angle of migration are also important parameters of Kirchhoff prestack time migration. The high-precision prestack time migration processing process is applied in Liuheying area of Langgu depression. The imaging accuracy is improved, the wave group features are clear, the migration is accurate, the breakpoint position is reliable, and the structure is prominent. Therefore, the research method in this paper is feasible and can improve the imaging accuracy.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P631.44

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