Research Of Efficient Storage Technology For Seismic Data

Against enormous pressure of transferring and storing large amounts of seismic data, a compression method suitable for Seg-Y(a common seismic data file), was proposed on the basis of the existing lossless compression algorithm in this paper. According to the feature that every seismic point data value was stored by four bytes in Seg-Y files,the whole seismic data were broken down into four groups, and distribution in the [0, 255] of the overall data and four packets were analyzed with Gini coefficient. It was found that the distributions of the four groups and the overall data were not the same, while the lossless compression methods were closely related to the distribution of data, so the method that a file was divided into four groups and each group was compressed individually, was determined. Then the compression ratios of different compression algorithm for each packet were compared by experiments, and the Lzma algorithm was selected to compress the first two groups while the Deflate algorithm was selected to compress the last two groups.Based on this and Microsoft.Net framework, using C# and Visual Studio2010, a compressed Seg-Y data transmission and storage software was designed in this paper. Seg-Y files were compressed and transmitted by client software, while they were received and stored by server software. At last, The efficiency differences on the network transmission between original data and compressed data, and on the compression ratio and decompression time compared to the current common archived software were tested. Experimental results show that the compression ratio of this paper is lower 8% than that of Lzma, lower 12% than that of Deflate, and lower 13% than that of BZip2 and Win RAR. The consuming time of this paper algorithm is between that of Lzma, BZip2, Deflate and Win RAR.Compared to transmitting original data, per megabyte of data can save an average0.23 s by this algorithm. Therefore, the proposed method can effectively reduce the compression ratio of Seg-Y files and reduce the time on network transmission.