1. School of Geosciences, China University of Petroleum(East China), Qingdao, Shandong 266580, China; 2. Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266580, China; 3. Geophysical Research Institute, Shengli Oil Field Branch Co., SINOPEC, Dongying, Shandong 257022, China
Abstract:When there are high impedence layer above and below a reservoir, strong reflections will shield reservoir reflection information on seismic sections.Therefore, we propose in this paper a dynamic matching pursuit method based on local frequency constraints to identify and separate strong reflections.Considering the "negative frequency" phenomenon of instantaneous frequency, we introduce local frequency to constrain the search range of the optimal atom of the dynamic matching pursuit algorithm.The local frequency is reasonable for the signal calculation, which can be used to identify the seismic wavelet that matches best the strong reflection.Using the local frequency and instantaneous phase information at the strong reflection position as a priori information, a dynamic waveform library is constructed to search for the wavelet that matches best the strong reflection.The strong reflection suppression coefficient is determined by signal tests to ensure that the equilibrium energy is consistent with the background energy after stripping strong reflection.This is helpful for picking up the reflection information of reservoirs and achieving reservoir characterization.The feasibility of the proposed method is verified by constructing model data with high impedence layer.Finally, the proposed method is applied to field data, which weakens strong reflection interference and highlights weak reflection.
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