摘要
地震勘探是目前寻找石油、天然气的主要手段,而从地震数据的分析中提取地层的速度资料—速度谱—又是地震数据处理中的重要一环.常规速度谱是对记录到的浮点地震数据进行计算的.取原始地震记录的符号位可得到每个数据只用一个二进位表示的符号位地震记录.本文用最小二乘法原理论证了在一定的假定条件下,可以对这种符号位数据进行类似于相关的运算—符号谱—来提取速度参数.这种方法从计算角度上讲能大大节省机器的内存和运算时间.本文从符号位把地震记录改造成等振幅波这一特性出发论述了符号谱具有能量团集中、分辨率高、层次清楚、连续性好、容易突出中、深层弱能量反射波和压制一些强随机干扰的特点.本文提出并讨论了实现符号谱的比较好的算法,并且在719机上进行了实践.实践结果证明,计算一个符号谱比做一个常规相关谱节省了40%的时间.本文附有用实际资料作符号谱和常规相关谱计算所得结果图的比较.比较全面地证明了上述符号谱的特点.
Abstract
At present, seismic prospecting is the major means of searching for oil and gas, and extracting velocity information, e. g. to find the velocity spectrum, from seismic data, is the key link of seismic data processing. The conventional velocity spectrum is derived from the recorded floating point seismic data. By using the sign bit of the original seismo-gram, one can obtain a sign bit seismogram indicated by binary digit. Based on the principle of the least square method, it has been proved that, under certain assumption conditions, the velocity parameters could be drawn from the calculation for sign bit data, the process of the calculation is similar to that of the correlation analysis. By the method introduced above, it is possible to save the internal storage and the operating time in a big way.For the cause that the real seismogram could be transformed to the seismogram with constant amplitude by dint of the sign bit, the sign spectrum thus has the following properties: the concentrated energy sets, the high resolution, the distinct reflected sequence, good continuity, the enhanced medium and deep reflections, the suppressed random noise, etc.In this paper, the author presented a better algorithm about the sign spectrum and made a discussion about it in a rather deep-going way. Besides, he has put this algorithm into practice on the computer Model 719. Practice has proved that 40% amount of work will be saved to do a sign spectoum calculation than that of doing a conventional correlative spectrum calculation. The material of the comparison of these two methods are also attached,
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