The Study And Application Of Inverse Q-filtering For Seismic Data

At present,oil and gas exploration is becoming more and more difficult.For some subtle reservoirs,the preservation and resolution of seismic data directly affect the results of reservoir prediction in the reservoir prediction process.Low-preservation and low-resolution In the seismic data,the deep amplitude attenuation is severe and the inphase axis is discontinuous,which makes it impossible to accurately identify certain geological structures and geological bodies during reservoir prediction,and affect the identification of favorable reservoirs.Therefore,improving the amplitude and resolution of seismic data is the premise and basis of reservoir prediction.When seismic waves propagate in underground viscoelastic media,different layers of different structures and material compositions will absorb and attenuate seismic wave energy.Due to this absorption attenuation,the high-frequency energy of seismic waves increases with the increase of propagation time.The low-frequency part of the energy decays rapidly,causing the seismic wave frequency to decrease and the frequency bandwidth to be narrow.At the same time,the seismic wavelet is distorted,the same phase axis is also distorted,and the seismic data resolution is low.At present,there are many methods to improve the resolution and amplitude preservation of seismic data,such as deconvolution and inverse Q filtering.Among them,anti-Q filtering is a method to compensate the attenuation effect of the earth,which can compensate the amplitude attenuation of the seismic wave and correct the seismic wave.The phase characteristics improve the continuity of the seismic data with the same phase axis,enhance the energy of the weak reflected wave,and improve the resolution of the seismic data.Existing anti-Q filtering methods,such as cut-off frequency method and stability factor method,due to the defects of the compensation formula,there are phenomena such as Gibbs effect in the compensated seismic record and serious rise of background high-frequency noise,resulting in earthquake The signal-to-noise ratio of the data is reduced,and the compensation effect is not good.Aiming at the above problems,this paper based on the relationship between quality factor and seismic wave amplitude compensation gain limit,based on the stability factor method inverse Q filtering,proposed "time-varying gain limit stability factor method inverse Q filtering",and solved the inverse Q filtering.The influence of the gain limit in the compensation process on the compensation effect is avoided,and the Gibbs effect caused by the piecewise function is avoided.This paper is based on the interpretation of gas-bearing seismic data for carbonate rocks and metamorphic rocks in a region of Bohai Sea.By conducting seismic data retention and high-resolution studies,we find a reasonable method suitable for this study area.The reservoir oil and gas analysis of the study area provides a basis for analysis.Through the research of this thesis,a new anti-Q filtering method is realized.The theoretical model and the application of actual data show that seismic data with high amplitude and high resolution can be obtained.The data will be used for later highquality reservoirs and gas-bearing predictions,with good results.