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自从在反射地震学中运用数字处理以来,随着计算机能力的提高,已经开发了许多新算法。在石油工业中已经出现了巨型并行计算机,并且认识到,在费用和性能方面并行机是很具吸引力的。本文中我们研究了地震模拟和叠前深度偏移的并行算法。使用伪谱法进行地震模拟要求2-DFFT,由于每个处理器仅包含有部分数据,因此不能用一步完成2-D FFT。因为必须进行数据交换,所以我们开发了一种并行的交换算法和一种并行的磁盘I/O方法,以减少计算时间。叠前深度偏移有许多理论算法。对并行计算,我们采用了频率和空间域的显式外推有限差分法。方法的实现采用了“并行频率切片”(parallel frequency slice)计算法,因为所开发的这些算法都是基于信息传递法(the message passing method),所以容易在工作站群上实现。
Since the application of digital processing in reflection seismology, many new algorithms have been developed as computer capabilities improve. In the petroleum industry there have been giant parallel computers, and it is recognized that parallel machines are attractive in terms of cost and performance. In this paper, we study the parallel algorithm of seismic simulation and prestack depth migration. Seismic modeling using pseudo- spectral methods requires 2-DFFT, and 2-D FFT can not be done in one step because each processor contains only a fraction of the data. Because of the need for data exchange, we developed a parallel exchange algorithm and a parallel disk I / O method to reduce computation time. There are many theoretical algorithms for prestack depth migration. For parallel computing, we use the explicit extrapolation of finite difference methods in the frequency and spatial domains. The implementation of the method uses a “parallel frequency slice” algorithm, as these algorithms are based on the message passing method and are therefore easily implemented on workstations.