【作者】 鲁彬；

【导师】 周立发；

【作者基本信息】 西北大学 ， 矿产普查与勘探， 2010， 博士

【摘要】 地震勘探作为现代油气勘探最重要技术方法之一,在现代石油勘探中发挥着巨大的作用,随着勘探程度的不断提高,对复杂地区的勘探工作日益增多。这就需要研究针对复杂地区的地震勘探、采集、处理技术。静校正、叠前去噪、偏移成像是复杂地区进行地震资料处理的重点、难点问题。特别是静校正,作为复杂地区地震资料处理中首先要做的工作,静校正处理效果的好坏不仅直接影响后续的处理步骤,而且影响着最终的成像效果。在地震资料处理中,静校正问题往往不是孤立存在的,它还影响着后续的去噪和速度分析等处理工作。随着地震勘探工作的区域由地形简单的平原转向地形复杂的山区,由二维观测系统逐渐转为三维观测系统,这些变化都给静校正处理提出了更高的要求。在常规资料处理中,通常假设地下介质是水平层状,表层速度横向变化比较缓慢,处理时先将地震数据校正到一个浮动基准面上,然后再进行处理,将最终处理成果校正到一个水平基准面上,但在复杂地区,地表起伏变化大,表层速度横向变化剧烈,岩性多变,表层结构复杂,基岩出露,给地震资料处理带来复杂的静校正问题。基于折射波技术理论的静校正方法是建立在水平折射面的假设基础之上的,在复杂山区很难找到一个稳定的统一的折射层,故基于折射波理论的静校正方法在此类地区不再适用。而基于几何射线理论的层析反演方法和基于波动理论的波动方程延拓静校正方法在此类复杂地区有着很好地应用效果。本文在对比研究多种静校正方法的基础上,从正演和反演两方面进行层析反演静校正方法研究。正演方面基于地震波射线理论,在传统网格最短路径和Fermat射线理论的基础上提出了适用于二维模型的网格最短路径迭代射线追踪正演方法,并进行了理论模型正演模拟,相比传统最短路径算法取得了较好的效果。在二维模型的基础上进行了三维模型网格最短路径迭代优化射线追踪正演方法研究,给出了具体的算法公式,并进行三维理论模型模拟。反演方面基于模糊数学理论,重点针对反演方程的求解,提出了利用模糊数学理论求解方程的反演方法,给出了具体的模糊反演求解的步骤。在以上正演和反演方法研究的基础上,提出了模糊层析反演静校正方法,并进行了理论模型速度反演计算。最后将模糊层析反演静校正方法应用与实际地震资料处理中,取得了较好的应用效果。基于射线理论的模糊层析反演静校正方法在复杂地区的应用效果要优于传统的初至折射静校正方法。在实际资料处理中也发现在有低速层调查资料的地区,应用本文提出的模糊层析反演方法有很好的效果,但在没有低速层资料的地区,由于无法建立较准确的初始速度模型,导致算法无法收敛,最终得到不理想的反演结果。这是模糊层析反演方法的缺陷所在,就这一问题还需进一步研究解决。更多还原

【Abstract】 Seismic exploration has become one of the most important technology in the area of exploring petroleum。It play vital function in exploring of the south foothill。Because of complex the earth’s surface and subsurface structure, there are a lot of difficulty in the other area. Static correction, eliminating perstack noise,migration are three critical technology. Especially static correction, it is first task in processing seismic data. The effect of static correction not only influence post-process but also decide the final effect of imaging.In seismic data processing, static correction problems do not exist in isolation, It directly affects the efficiency of other processing steps, such as noise removal and velocity analysis. With the terrain of seismic exploration is expand from simple to complex, for 2D to 3D, which call higher request on the static correction method. Upon the conditions of conventional static correction method, we usually assume that layer occurs as horizontal bed, the velocity of surface layer slow-varying, section can be scaled to a chosen planar measurement level with kinematic. But, there are large relief degrees surface and large variable lateral velocity in complex area, which cause difficulties for static correction. The Refraction Statics is on the basis of refracted wave theory, it is very difficulty to find one stably refracting layer in complex areas. So the refraction statics method is unfit these areas. However tomographic inversion static correct on the base of geometric ray theory and wave equation continuation static correct on base of wave theory can get a satisfaction result in complex areas.In this article, on the base of studis and comparision of many static correction methods, author research tomographic inversion static correction method from both the forward and inversion. In terms of the forward, on the base of grid shortest path algorithm and Fermat ray theory, a method of shortest path raytracing by iterative optimization was come up. The method was applied to theoretical model and excellent effect has been obtained. On the base of two-dimensional forward model, author research method of shortest path raytracing by iterative optimization in three-dimensional. In terms of the inversion, focus on a solving, author come up a fuzzy math method the reverse equations. On the base of forward and inversion method, author purpose a fuzzy tomographic inversion static correction method,apply the method to processing the practical seismic data and gets good effect. There are low-depression layers velocity data in some areas, the fuzzy tomographic inversion static correction method can get good effects, but in some arear where are not low-depression layers velocity data, the method get very poor effect. The main explanation to these results is that exact fuzzy rule can not be set up in these area. The problem needs further research and summarization.更多还原