Detection of Oil-Filled Channel Using Time-Frequency Spectral Decomposition
Maryam Nejati, Mohammad Ali Riahi · GEO 2010 · 2010
Due to difficulties in observating many characteristics of a time-series in time domain, it can be studied in the frequency domain. In fact, amplitude and phase spectrum have the ability to determine a timeseries for us. Therefore, for a detailed study of time-series, we transform it from one-dimensional domain to time-frequency domain. Because the transition from time domain to frequency domain provides possibility to survey frequency content of a signal and consequently it provides detailed study of many characteristics of the time-series. For this purpose the spectral decomposition which is an efficient method has been used in recent years (Kastagna and colleagues, 2003). Spectral decomposition method is an useful tool in interpretation of seismic data and seismic exploration also. In fact, analysis of data to their spectral components can specify many of structural and stratigraphy details below the earth surface. Spectral decomposition help us in detection of stratigraphy traps and frequency content changes due to hydrocabore. The spectral decomposition allow the interpreter to use the discrete frequency components of the seismic bandwidth for interpretation and study the exact details of stratigraphy below the earth (Chapra and Marfort, 2006). Different spectral decomposition methods include short time Fourier transform (STFT), s transform, Matching Pursuit and continuous Wavelet transform(CWT), that by using each of these methods we can enhance the time and frequency resolution. Continuous Wavelet Transform (CWT) techniques, which are the same as narrow-band spectral analysis methods, provide frequency spectra with high temporal resolution without the windowing process associated with other techniques CWT method is useful for detecting hydrocarbore reservoir, because these reservoir were detected in low frequencies. Identifying channels and detection the lithology within them have always been a topic of interest among geophysists. This paper presents a successful application of the CWT method in identifyihng buried channels in one of southern oil fields of Iran.