Study On Seismic Wave Propagation Under Complex Near Surface And Methods Of Energy Compensation

With the advancement of oil and gas exploration, more and more researches are focus on the complicated lithologic or subtle hydrocarbon reservoirs. So it correspondingly demands a much higher resolution of seismic data.Near surface medium will largerly affects seismic wave propagation because of its specially properties, and causes seismic wave changes in the propagation direction, waveform, frequency spectrum and the energy and other aspects. It will hardly damage effectiveness of seismic acquisition and processing technology. So it is necessary to deal with study on complex near surface seismic wave propagation, and develops near-surface parameters inversion methods to investigate the near surface structure. Then we apply energy compensation on seismic data, at last improve resolution of seismic data.On the one hand, this study targets on near-surface medium properties and seismic wave attenuation law and the analytical methods. It mainly introduces the near-surface characteristics of "low-speed low-density", "low quality factor", "free surface", "refraction interface" and other features. Then we theoretical study and stimulate seismic "excitation", "acquisition" and "propagation" on the near-surface characteristics, and achieved some useful seismic wave laws within near-surface characteristics.On the other hand, we extract near-surface parameters of attenuation and velocity, so as the near-surface inversion of viscoelastic properties and parameter extraction. Based on investigation of near-surface parameters inversion methods, we study methods of extracting absorption and velocity paramaters from borehole microlog, and apply to field data processing. With the inversion output, we establish"near-surface comprehensive model". Through above studies, the ultimate goal is to obtain the law of seismic wave propagation in near surface media, and contribute to the excitation and reception in seismic acquisition services. Then establish "near surface comprehensive model", with the help of seismic forward and wavefield analysis, it will contribute to the seismic acquisition, processing, and interpretation.At last, based on the established "near-surface comprehensive model", we develop energy compensation methods on seismic datas.It involves time-frequency-space domain energy compen- sation based on data, and inverse Q filter methods based on dynamic characteristics. Inverse Q filter methods include Hale's and stabilized methods. We test the method with theoretical models, then analyse and compare three different processing results. We process actual prestack and poststack seismic data, and analyse application effectiveness with different motheds. During actual processing, we can combined time-frequency-space domain energy compensation and stabilized inverse Q filter methods, thus achieving the goal of seismic resolution improvement and deep weak signal energy compensation.