Joint inversion of quality factor based on upgoing and downgoing waves

摘要

Quality factor Q is a key parameter describing seismic wave attenuation. Estimating Q accurately is important to seismic data processing and reservoir characterization. Downgoing and upgoing waves are coming from above and below the receiver containing the strata information, respectively. Downgoing wave has always been the key in Q inversion, while the upgoing wave is seldom used. Thus, the information contained in the upgoing wave is not fully utilized, leading to problems of multi-solution and low accuracy. To fix these problems, this study proposes a joint inversion method of Q, which uses both upgoing and downgoing waves. The nonlinear relation among the upgoing wave, downgoing wave, and Q value is jointly used to construct an objective function, which measures the energy difference between the actual and calculated amplitude spectra. As the energy between upgoing and downgoing waves is not balanced, to balance the weight of the two kinds of waves in Q inversion, a weight coefficient is used to adaptively control the weight of them. The optimal Q can be estimated by minimizing the objective function. Numerical simulation results indicate that the proposed method can reduce the effect of frequency band selection, and provide more accurate results. The application on field data demonstrates that good results can be achieved, and the estimated Q has great potential in reservoir characterization.