Time-frequency Analysis Of Seismic Signal And Its Application To Thin Reservoir Identification In Su Lige Gas Field

This thesis introduces time-frequency analysis of seismic signal and its application to thin reservoir identification in the Su Lige Gas Field. The main content of the thesis are as follow:1. General time-frequency analysis methods are introduced, including short-time Fourier transformation, wavelet transformation, Wigner-Ville distribution; and the disturb terms and suppression methods in Wigner-Ville distribution are discussed.2. It gets the result that the smooth pseudo Wigner-Ville distribution has the best time-frequency resolution and eliminate the disturb terms by comparing these methods.3.The basic theory of Hilbert transformation and Hilbert-Huang transformation are introduced; and comparing two methods in extracting instantaneous frequency gets the result that if signal is non-stationary or contains noise, instantaneous frequency may be negative and lose the practical significance in Hilbert transformation; but instantaneous frequency has the practical significance in Hilbert-Huang transformation, as signal is decomposed several Intrinsic Mode Function by empirical mode decomposition firstly, then in Hilbert transformation.4. Su Lige Gas Field is the largest reserves of natural gas fields in china. The characteristic is relatively simple structure but thin sandstone reservoirs and fast variation in horizontal so that it is difficult to be identified in seismic records. The Use of smooth pseudo Wigner-Ville distribution and Hilbert-Huang transformation analyzed 2-D seismic data of one block in Su Lige Gas Field. According as well data, the study on th??solution of seismic time-frequency analysis identify thin reservoir. The result shows that smooth pseudo Wigner-Ville distribution can identify about 10m sandstone reservoir; Hilbert-Huang transformation can identify 10~20m sand bodies.