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Study on Data Compression Techniques Applicable to Downhole Instruments

In MWD system or logging system, tomographic imaging technique is more intuitive and reliable in reservoir characterization description compared with conventional logging data. Moreover, the tomographic imaging technique is much better than other logging data in describing such inhomogeneous formations as fracture, dissolution and so on. But the tomographic imaging technique involves a large amount of data, and the downhole instrument operation speed and data storage space are limited; therefore, data compression technology should be used so as to save more data in order to accurately describe the underground information. Whether the data compression technique used is proper is contingent on measurement speed, measurement density of the instruments. In this paper, two data compression techniques are analyzed, which are discrete cosine transform (DCT) and digital bit reduction. And the important parameters such as data compression ratio, and resolution and applicability are compared according to the calculation results. Furthermore, the application effect and application direction of the two different data compression techniques are verified, which has an important practical significance for the design of imaging logging instruments.