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目前,三维观测可大可小,或是以直线穿越沙漠、冻土带,或是沿风道穿过森林、丛林。三维采集需要周密地计划,因此研究野外产生的多种复杂情况是十分重要的。现在已有计算机程序可帮助勘探人员做这项工作。三维设计主要依靠解释人员,他们必须分析可能的地质目标,确定期望的覆盖次数(以及信噪比)和面元大小(决定空间分辨率和倾斜同相轴的最大无畸变频率)。到达目的层的射线路径决定最大和最小容许炮检距。限定三维观测的基本公式是: NS=F/(NC.b.b) SLI=1/(NS.b.2)NC=记录道数,b=面元大小(米),NS是产生F次覆盖时,每平方米所需炮数,SLI=炮线距。检波线间距依赖于最小容许偏移距并决定排列方式一直线型、砖块型、齿型、方格型等。加大检波线距自然能减少施工成本。而从野外施工人员和处理人员的角度看每一种排列方式都有利有弊,必须予以分析。用这样一种方式采集资料时速度分析、静校、DMO切除、偏移的效果如何?是否资料中的任何噪声都能经叠加而去除(用检波器组合消除线性噪声,大偏移距消除多次波)?对每一CDP面元作覆盖次数,偏移距和方位角分布的全面分析是至关重要的。最后,野外施工方面的问题必须考虑,设备的安置和移动是费钱的。不同的设计可以节约成本(与进入与退出测线相比)。计算机程序应当能提供简便的炮点移位以满足湖泊、河流、管线及建筑群区的跨越放炮,或填充沿非直测线激发、接收形成的“空白区”。设计过程中的每一步都应能进行调整且简单易行,最终完成成功、高效的三维地震采集。
At present, the three-dimensional observation can be very large or small, or straight through the desert, tundra, or through the air duct through the forest, jungle. Three-dimensional acquisition requires careful planning, so it is important to study the many complexities that occur in the field. There are computer programs available to help the prospectors do the job. The three-dimensional design relies mainly on the interpreter, who must analyze possible geological targets, determine the expected number of overlaps (and signal-to-noise ratio), and bin size (the maximum undistorted frequency that determines spatial resolution and tilted events). The ray path to the target layer determines the maximum and minimum allowable offset. The basic formula for defining 3D observations is: NS = F / (NC.bb) SLI = 1 / (NS.b.2) NC = number of tracks, b = , The required number of gun per square meter, SLI = gun line distance. Detection line spacing depends on the minimum allowable offset and determine the alignment of a straight line, brick type, tooth type, square and so on. Increase the detection line spacing from nature to reduce construction costs. However, each arrangement has its advantages and disadvantages from the perspective of field construction workers and handlers and must be analyzed. What is the effect of speed analysis, static calibration, DMO removal, and offset when capturing data in such a way? Any noise in the data can be removed by superposition (using a combination of detectors to eliminate linear noise, eliminate large offset errors Sub-wave) • A thorough analysis of the number of coverage, offset and azimuth distribution for each CDP bin is crucial. Finally, problems with field construction must be considered, and the placement and movement of equipment is costly. Different designs save costs (compared to entering and leaving the survey line). The computer program should provide easy spot-by-spot shifts to cover lakes, rivers, pipelines and buildings across the shot, or to fill “blanks” created by exciting and receiving along non-straight lines. Every step of the design process should be easy to adjust and easy to accomplish with successful and efficient 3D seismic acquisition.