The Study On Seismic Data Resolution Enhancement Via Inverse Q-filtering And Continuous Wavelet Transform Methods

The reasons that influence seismic resolution include seismic wavelet,acquisition method,signal-to-noise ratio and earth Q-filter et al.This dissertation do some research on enhancing seismic resolution associated with seismic wavelet and attenuation.When propagating through subsurface materials,the amplitude of the seismic signal will be attenuated and the phase will be distorted which is usually called earth Q-filtering.During processing,inverse Q-filtering is always used to compensate for the earth Qfilter,and it can compensate for amplitude attenuation and correct phase distortion,which will improve the resolution of seismic data.However,as the amplitude compensation operators will be enlarged by an exponential function,the high-frequency computation error and noise will be amplified seriously,causing instability.The most popular stabilization method of inverse Q-filtering is the gain-limited stabilization operator algorithm proposed by Professor Yanghua Wang.This method achieves stable calculation of inverse Q-filtering,but the compensation bandwidth is limited by the given limited-gain,and in some circumstances the high-frequencies are suppressed in wide band data.After analyzing the previous research,this dissertation proposed shaping regularization inverse Q-filtering.This method can not only achieve stable inverse Q-filtering but also improve compensation bandwidth and accuracy.Bandwidth extension technology is used to recover the high-frequencies and lowfrequencies.This dissertation process seismic data by CWT and calculate the harmonics and sub-harmonics according to the chosen fundamental frequencies.After adding the harmonics and sub-harmonics back to the seismic data,the bandwidth of seismic data is extended.This method can add the harmonics and sub-harmonics associated with the reflections,and those that have nothing to do with the reflections won't influence the calculation,which will keep the signal-to-noise level during enhancing seismic resolution.By testing real seismic data,these two methods can enhance the resolution of seismic data effectively.Shaping regularization inverse Q-filtering can achieve stable inverse Qfiltering and compensate for amplitude decay much more accurate.Extension method based on harmonic can add the harmonics and sub-harmonics associated with the reflections in case of decreasing the signal-to-noise level.