Method for compressing and decompressing acoustic logging data

Abstract

The invention discloses a method for compressing and decompressing acoustic logging data. The compressing method comprises the steps: conducting matrix partitioning on the data collected by an acoustic logging instrument according to the number of collection channels; carrying out discrete cosine transform on each block matrix to obtain a DCT coefficient matrix; designing an appropriate quantization matrix according to the characteristics of the sound wave signals, and quantizing the DCT coefficient matrix; carrying out run-length coding and Huffman coding on the quantized matrix; and obtaining a compressed code stream and transmitting the compressed code stream. According to the compressing method, on the basis that the calculation performance of a downhole main control device is improved, a high compression ratio is achieved. According to the method, the data can be compressed in real time downhole, and the data transmission amount is greatly reduced, so that the logging speed of the acoustic logging instrument is increased.

Description

technical field [0001] The invention relates to the technical field of data compression, in particular to a method for compressing and decompressing acoustic logging data. Background technique [0002] With the development of logging technology and integrated circuits, higher requirements are put forward for the detection accuracy, speed and detection distance of logging tools. Among various acoustic logging tools, the remote detection multipole array acoustic logging tool has the largest amount of data, and is limited by the communication rate of the data transmission system, the remote detection multipole array acoustic logging tool often has a slower logging speed. [0003] In the existing acoustic logging data compression technology, use the ADPCM compression method, input 16-bit data, the compression ratio is 4:1, input 12-bit data, the compression ratio is 2:1; Chinese patent application (CN201110408530) discloses "a three-dimensional The data compression method in "...

AI Technical Summary

Problems solved by technology

Among various acoustic logging tools, the remote detection multipole array acoustic logging tool has the largest amount of data, and is limited by the communication rate of the data transmission system, the remote detection multipole array acoustic logging tool often has a slower logging speed

[0003] In the existing acoustic logging data compression technology, use the ADPCM compression method, input 16-bit data, the compression ratio is 4:1, input 12-bit data, the compression ratio is 2:1; Chinese patent application (CN201110408530) discloses "a three-dimensional The data compression method in "Real-time Compression Method of Acoustic Logging Data" splits the original data into high and low bits to be compressed, and then performs DCT to obtain the mapping data, and then reserves more bits for the data with large values ​​in the mapping data , the smaller number of digits is retained to achieve data compression, but this method can only achieve a compression ratio of 50%; Chinese patent application (CN201610430622.7) discloses "a real-time compression method and decompression method for LWD data According to the data compression method in ", design a multi-resolution quantization model according to the specific data, formulate a quantization table, calculate the difference between adjacent data, use the quantization table to process the difference, obtain the quantization value and its coordinates, and finally carry out the coordinate value transmission

[0004] With the development of logging tools, the compression ratio achieved by the above logging data compression methods can no longer meet the actual logging needs

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