The application of spectral analysis of logs in depositional cycle studies
WANG Gui wen, DENG Qing ping, TANG Wei qing (University of Petroleum, Beijing 102249, P. R. China)
The characters of strata are shown continually and sensitively by well logs, which include a great amount of geological information. The purpose of well log interpretation is using various tools and technologies comprehensively to tap the strata information which is involved in logging data, to set up the relations between logging data and geological objective and to describe the geological characters of the targets. The subject of studing sedimentary cycles of the reservoir is small scale cycles of strata. Well logging data became the main sources of small scale cycle study duo to their many good characters such as good continuity and large quantity. The periodic occurrence of any sedimentary event may be expressed by the frequency in the time series. During the course of deposition, the periodicity of sedimentary cycle may be embodied in the logging data. Some data processing systems can be designed for extracting the information from the logging data and the deposition characters can be analyzed, described and identified with the information extracted from the logging data. The authors of this paper put forward a method called the maximum entropy spectra analysis, which can extract the major composition from logging data, do the the maximum entropy spectra analysis and spectra character analysis, and then identify and study sedimentary cycles according to the width of spectra and its rhythm. Compared with other spectra analysis, such as Fourier entropy and periodic picture, this method has many advantages such as no limit to sampling length and higher resolution to the spectra. The results of processing actual data from the Tarim basin show the feasibility and validity of this method.
【CateGory Index】： P618.13