Spectral decomposition is a new technique for seismic reservoir research that transforms seismic data from time domain to frequency domain by discrete Fourier transform or maximum entropy approach.According to the theory of seismic wave propagation

this paper deduces the amplitude spectrum expression of thin beds and confirms their notches characteristics of spectrum

i.e.the reciprocal of notches period equals to the temporal thickness of thin bed.With this principle

we discuss ideas and methods of estimating reservoir thickness based on spectral decomposition.In practice

quantitative interpretation of reservoir thickness is realized by establishing a precise velocity field of targets and computing the first spectral peak frequency in target tuning cube.The application shows that the prediction results are consistent with the drilling data

indicating they are credible.Spectral decomposition provides a new approach and method for quantitative seismic interpretation of reservoirs and has broad application prospects.