Research On Deep Layer Seismic Absorption Mechanism And The Method Of Energy Compensation

With deep layer becoming the major objective of seismic exploration, high quality seismic data was needed. In order to improve the signal-noise(S/N) ratio and resolution of deep seismic data, deep layer seismic absorption mechanism, deep de-noising technology and energy compensation technology was studied.This paper studied the main factors influencing seismic wave attenuation, which can be summarized as the following:â‘ The factors related to underground geological conditions, such as the reflection coefficient, the focus and divergence caused by reflection interface shape, absorption arising from the formation of non-elastic formation, multiple reflections caused by thin alternating layers, the scattering caused by inhomogenous;â‘¡The relevant factors related to near-surface conditions , such as the strength and coupling of the source, detector sensitivity and coupling, the strong absorption caused by the near-surface stratigraphy loose;â‘¢The factors related to offset, such as spherical divergence, absorption changes caused by different transmission path.In order to enhance signal energy in deep layer, the S/N ratio must be improved. This paper presents a segmentation surface wave suppression using 2-D wavelet transform. Compared with conventional FK filtering, the advantages of this method is to maximize maintain effective wave. In addition, the advantages and disadvantages of the KL transform, f-x forecast de-noising, wavelet threshold de-noising was compared: When the events are horizontal, the conventional KL transform can enhance the events; but when the events are oblique or curving, using the conventional KL transform will destroy the continuity of effective events; F-x forecast de-noising adapt to linear events. When the events are not linear, using f-x forecast de-noising will cause event distortion. 2-D wavelet transform de-noising have good result in maintaining signal energy and suitable to low S/N data.For the earth attenuation, time-frequency analysis of energy compensation technology has been presented. The biggest advantage of this method is does not need to know the quality of formation, which seek to avoid the formation of this absorption coefficient, so that this method can be widely applied. Model spreadsheet and the actual data processing test proved the validity of the method.