Spectral Analysis In Applied Research, Well Logging Interpretation

One of the main tasks of the logging interpretation is to identify the oil-layer, gas-layer, water-layer and dry-layer accurately with research of logging data and evaluate capacity of oil & gas production.Spectrum has been used widely in engineering. In logging interpretation, it has been used for researching the problem such as sedimentarycycle of reservoir. In this paper, spectrum is used for logging data processing and identifying the fluid property of reservoir.There are many ways to estimate the spectrum and it is very important to choose a suited way. In this paper, some ways of spectral estimation are discussed and used for oil logging interpretation. On one hand, estimating the spectrum of the logging data and utilizing spectral diagram to identify oil-layer, gas-layer, water-layer and dry-layer; On the other hand, utilizing several important parameters of spectrum and combining discriminant analysis to return to classify and identify the fluid property of reservoir quantitatively.In this paper, we offer the theories of hide periods and covariance matrix and use them to identify the fluid property of reservoir.Analysing hidden periods of logging data is a kind of method to find out component of period of logging data and utilize the difference of component of period to identify fluid property of reservoir. In this paper, we discuss the way detailed.There are more than ten logging curves which can reflect property of rock strata and they are associated. In this paper, we offer covariance matrix to identify fluid property of reservoir.In the end, software system for logging interpretation is programmed by the applied mathematical software MATLAB 6.5 based on the operating system Windows98, 2000 and WindowsME/NT/XP. Its application in logging data of some oil-field confirm that the technique is excellent, which greatly increases the accuracy of interpretation and contributes a new way of logging interpretation.