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目前采集地震数据的CDP(共深点)方法有一些缺陷。它不能充分记录最佳短炮检距上最强的反射信号以提高信噪比。在弱信号区,这种方法不能很好控制静校和动校。不精确的静校、动校以及地下速度异常都能引起叠加信号的时变失真,以致无法有效地确定小矿体。在地层储油构造勘探中,不能可靠地研究反射波和岩性的“特性”变化,是因为在CDP叠加段上很难得到正确的信号波形,这不仅是由于不精确的静校、动校和速度异常会引起信号畸变,而且还由于某个深度点的这些个别CDP叠加道信号也会发生变形,致使信号在叠加后的波形已不再是该深度点的真实波形。因为在叠加前已对静噪声进行了抑制,所以CDP方法的地震剖面的浅层部分并不总是可以利用的。CDP方法成本较高,特别是为了得到有效数据,需要采用高次叠加时,成本就更高。为了克服上述困难,设计了一种与一个或多个炮点或炮点组合有关的采集地震数据的方法,根据工作需要,可以在同一点或邻近的点上重复放炮,而一些互相很接近的检波器组则是埋置在短的、最佳的并且是固定的炮检距上(见图1)。根据每个炮点的检波器组所记录的这些道在静校和动校后叠加,其输出道就是共反射点。在勘探中顺着各条测线进行数据记录,每条测线上的炮点可根据需要,按规则的短间距或长间距设置,而炮是一炮接着一炮地放的(见图1)。利用每条测线上各个炮点的叠加输出道可得到该测线的地震剖面。检波器组可埋置在各炮点的两侧,或者是沿测线方向的一侧.当检波器组埋置在炮点的两侧时,每侧的这些道在一起叠加,因此每一炮可得到两个叠加输出道,若炮点间隔适当,则一个炮点正向边的输出道就可以和下一个炮点的反向边输出道作CDP叠加,产生一条测线的最终剖面。如果在原先的勘探区中没有CDP数据,那么,有些测线就要利用UDP方法的第一次放炮来选择这一方法的各种记录和处理参数,并在采集的数据解释中使用。这种方法解决了CDP方法中的问题。其主要优点是省钱,并可得到最小失真的数据。
The current CDP (Total Depth) method of acquiring seismic data has some drawbacks. It does not adequately document the strongest reflected signal at the best short shot to improve signal-to-noise ratio. In the weak signal area, this method can not control the static and dynamic school. Inaccurate static, dynamic and underground velocity anomalies can cause time-varying distortion of superimposed signals, making it impossible to effectively determine small ore bodies. In stratigraphic reservoirs exploration, the “characteristic” changes of reflected waves and lithologies can not be reliably studied because it is difficult to get the correct signal waveform in the CDP superimposed section, not only because of imprecise static and dynamic And velocity anomalies can cause signal distortions, but also deformation of these individual CDP superimposed track signals at a certain depth point causes the waveform of the signal after superimposition to no longer be the true waveform at that depth. Because of the suppression of quieting noise before stacking, the shallow part of the seismic section of the CDP method is not always available. The high cost of the CDP method, especially in order to obtain valid data, requires a higher cost when using higher order overlays. In order to overcome the above difficulties, a method of acquiring seismic data related to one or more shots or shots is designed. Depending on the needs of the work, shots can be repeated at the same point or at adjacent points, while some are close to each other The geophone is embedded in short, optimum and fixed offset (see Figure 1). The tracks recorded by the geophone group for each shot point are superimposed after static and dynamic correction and the output tracks are common reflections. Data is recorded along the survey lines during the exploration. The shots on each survey line can be set according to the needs of the short or long intervals of rules, while the guns are shot one by one (see Figure 1 ). The seismic profile of the survey line is obtained using the superimposed output tracks for each shot on each line. The geophones may be embedded on either side of each shot or on one side of the survey line When the geophones are embedded on either side of the shot, the tracks on each side are superimposed together so that each Two superimposed output lanes can be obtained. If the shots are spaced properly, the output of a shot at the forward side of the shot can be CDP-superimposed with the reverse shot of the next shot to produce the final profile of a survey line. If there is no CDP data in the original exploration area, then some gauges will use the first blasting of the UDP method to select the various logging and processing parameters for this method and use it in the data interpretation of the acquisition. This method solves the problems in the CDP method. The main advantage is saving money and getting the least distorted data.