Using four-hole survey data to estimate the near-surface Q value

Near-surface quality factor estimation and compensation have become an important field of research for high-resolution seismic exploration.Uphole surveys are widely used to investigate near-surface structures because of their simple operation and low cost.However, the conventional method is affected by differences in the response of source wavelet and geophone coupling, which significantly reduce the estimation accuracy of the near-surface Q value, and there is substantial uncertainty in the investigation results of near-surface absorption structure.Therefore, a new four-hole observation system for estimating the near-surface Q factor is proposed herein to simultaneously eliminate the influence of the differences in response of source wavelet and geophone coupling.The influence of near-field and high-frequency noise on Q factor estimation is effectively eliminated by optimizing the frequency band range.Application results showed that the proposed method can obtain a stable and reliable near-surface Q factor.Therefore, absorption compensation can be applied to the seismic data using an inverse Q filter based on wave field continuation.The resolution of the seismic data significantly improved after absorption compensation.