【作者】 何永清；

【导师】 刘学伟；

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

【摘要】 青海省柴达木盆地柴西南区地形地貌比较复杂,地表类型多样,包括山地、沼泽、湖泊、戈壁、沙漠等各种地形,表层岩性及表层结构变化快,导致原始资料信噪比低;地下地质结构比较复杂,断裂系统发育,并且纵横交错,导致地震资料成像困难。随着油田勘探开发的不断深入,对地震资料品质的要求越来越高,以往的地震勘探采集技术、方法及获得的资料已不能满足当前油田勘探开发的需要。本文针对柴西南区特殊的地震地质条件,在地震采集技术方面进行深入研究,并取得一些新的成果和认识,提高了地震资料品质。在观测系统方面,首次在柴达木盆地地震勘探中引入基于叠前偏移设计观测系统的理念,充分利用CRP覆盖次数分析、波动方程正演模拟以及照明分析等论证手段的结合,完善了基于叠前偏移成像的三维观测系统设计和优化流程,在昆仑山前进行了激发效果与叠前成像效果之间关系的探索;分析了炮、道密度对观测系统压噪能力的影响。在近地表调查方面,有效探索了巨厚风成沙漠区和结晶盐区的表层结构调查,为激发方法优选和静校正计算提供了依据。在静校正计算方面,认为模型约束下的初至波折射静校正为目前效果比较明显和实用的一种方法,其判断依据主要为第四系的成像效果。在炸药激发方面,根据地质任务优选岩性激发和根据压噪效果优选激发方式,提高激发效果。在接收方面,对比了不同检波器类型、不同组合方式、不同组合基距的接收效果,研究过程中还根据结晶盐区的实际情况改进了提高耦合效果的检波器埋置工具。通过对地震采集技术各方面的深入研究,形成了一套适合于柴西南地区提高分辨率与构造成像精度的高精度三维地震资料采集方法和工作优化流程,有效地指导了柴西南区的三维地震勘探工作。首次提出并深化认识了“三个面”(潮湿层底界面、沙层底界面、第四系底界面)在风成沙漠区和戈壁砾石区地震勘探中的关键作用。这些技术和方法的应用,有效满足了油田勘探开发当前的迫切需要,拓展了柴西南区的勘探范围和前景,为昆北油田的发现奠定了地震资料基础。更多还原

【Abstract】 The research area is located at the Southwestern Qaidam Basin in Qinghai Province, and there are complicated topography and various types of surface, including mountains, swamps, lakes, desert, etc. Owing to quickly change of near-surface lithology and structure, poor data quality, such as very low signal to noise ratio, is normal in raw seismic data. Complicated subsurface structure and those developed fault with crisscross make the imaging difficult. With the deepening of oil exploration in the field, seismic data obtained in the past cannot meet the current needs of oil exploration and exploitation, due to old seismic acquisition techniques and equipments.According to the special geological conditions in the southwest Qaidam basin, this paper focuses on the study of seismic acquisition technology for improving the quality of seismic data, and getting some new results or ideas. In the geometry design, the idea based on pre-stack migration is first introduced to the seismic exploration in the Qaidam Basin. Combined the analysis of CRP folds with wave equation modeling and illumination analysis, this method improves the 3D geometry design based on pre-stack migration and optimization process. Probing the relationship between improving the single shot quality and increasing source density will contributed to improving the data of pre-stack migration in Kunlun Mountain. And it was served as analyzing the influence of receiver density and source density on noise attenuation of the geometry. In the near-surface investigations, this study focuses on the surveying of the thick wind-built desert area and the crystalline salt area, which provides the basis for selecting the shot method and computing static correction. Mainly based on their judgments of the imaging results for the base of Quaternary, first-break refraction static correction constrained by the correct model is proved a effective method in computing the statics. In dynamite shooting, the good shooting lithology and its ability of noise attenuation are key considerations to improving the seismic data quality. In receiving, it had been done for comparing the effect of seismic data with different types of geophones, different group geometry and different group interval. The coupling effect of the special geophones embedded tools is improved as well.Having been research seismic acquisition in deep, a set of higher resolution and high-precision data acquisition methods is formed for effectively guiding the 3D seismic exploration in southwest Qaidam basin. And this method is effective in the practice. This study has put emphasis on the key role of "three bottom interface" in improving seismic data quality of desert area, which are the wet sand bottom boundary layer, the sand bottom interface and the bottom of Quaternary interface. The implementation of these technologies and methods effectively meet the current exploration, and the seismic data contributed to find Kunbei oilfield.更多还原