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Time-varying wavelet phase extraction is an important problem when extracting the time-varying seismic wavelet from real seismic data. In order to break through the limitation of constant phase or piecewise stationary assumption in the existing phase estimation methods, a new phase extraction method of time-varying seismic wavelet is researched in this paper. The propagation and attenuation law of seismic wavelet is analyzed at first, and the relationship between the amplitude and phase spectra of time-varying wavelets is obtained by deriving the wave equation for a viscoelastic medium. And then according to the relationship, time-varying wavelet phase can be extracted using the estimated time-varying wavelet amplitude. The numerical simulation results demonstrate the effectiveness and feasibility of the proposed method. The research productions will be important for improving the resolution of seismic data.
Presentation Date: Wednesday, September 27, 2017
Start Time: 3:05 PM
Presentation Type: ORAL
Zheng, Jiangfeng (China National Offshore Oil Corporation (CNOOC) Ltd., Tianjin Branch) | Zhang, Zhijun (China National Offshore Oil Corporation (CNOOC) Ltd., Tianjin Branch) | Sun, Jialin (China National Offshore Oil Corporation (CNOOC) Ltd., Tianjin Branch) | Zhou, Xing (China National Offshore Oil Corporation (CNOOC) Ltd., Tianjin Branch) | Xu, Dekui (China National Offshore Oil Corporation (CNOOC) Ltd., Tianjin Branch)
More and more research shows that in BoHai oilfield the amplitude spectrum of reflectivity is always a “blue spectrum” and non “white spectrum”, and the wavelet is mixed-phase. So the “blue” deconvolution is proposed to obtain the real reflectivity. The high-order statistics method can estimate the wavelet accurately, and by using the wavelet the deconvoltion results can be improved effectively. Applications in many exploration wells and development wells in BoHai Bay show the recognition of thin interlayers whose thickness is blow 5 meters is improved obviously, and the reservoir’s connectivity can be described more accurately.
Presentation Date: Wednesday, September 27, 2017
Start Time: 10:35 AM
Location: Exhibit Hall C/D
Presentation Type: POSTER
In Matsuoka and Ulrych (1984), phase information is obtained using nonparametric, Fourier-type bispectrum estimates that produce limited resolution and highvariance estimators, just as the traditional Blackman-Tukey techniques s11.5 Tomographic Wavelet Estimation
This paper analyzes the capability of the phase spectrum and amplitude spectrum of bispectrum to differ from the different phase systems and the sensitivity of the phase spectrum and amplitude spectrum with respect to the little change of the amplitude caused by fractures. To be further, after the virtue and defect of bispectrum(which includes phase spectrum and amplitude spectrum) in fractured zone detection is argued by forward model, a new way in fractured zone detection is arisen as the following: firstly, phase spectrum, which is more sensitive to the little change of amplitude and resistant to the stochastic noise than amplitude spectrum, can predict the local fracture distribution well; secondly, amplitude spectrum, which is good at detecting the fracture to produce significant change of amplitude, rather can predict the whole fracture distribution well. Another method of time-frequency is also used in detecting the seismic fractured zone. The purpose of this study is to find the effective method to detect the seismic fractured zones.
The reservoirs of the Guantao Formation in the Penglai area of the Bohai Oilfield are thin and interbedded. The seismic response energy is weak, the continuity is poor, the resolution is low, and even weak white reflections appear, which brings great difficulties to reservoir identification. Aiming at this problem, this paper takes the Penglai block as an example to analyze the seismic response characteristics and the genetic mechanism of the Guantao Formation from the statistical analysis of the well seismic data and the forward simulation results. Aiming at the seismic response of Guantao Formation, based on diffusion filtering, a hybrid phase wavelet extraction method based on time-frequency spectrum simulation to extract amplitude spectrum and extracting phase spectrum in complex spectrum domain is proposed for deconvolution processing. Therefore, the seismic profile noise is suppressed, the continuity of the seismic axis is enhanced, the seismic response resolution of the target interval is improved, and the seismic data quality is improved. The ideal effect is obtained in the reservoir prediction of the Guantao Formation in the Penglai area of the Bohai Oilfield. Note: This paperÂ wasÂ acceptedÂ into the Technical Program but was not presented at the 2020 SEG Annual Meeting.