3D Seismic Imaging Technology and Its Application in GCD Work Area of Tarim Basin
The GCD work area of the Tarim basin is covered by desert,where the acquired seismic data are superimposed with high-energy sand dune resonance noise due to the loose and thick dune structures,hampering the accurate imaging of the Ordovician marine reef-beach reservoir.Conventional imaging methods are disadvantageous due to low resolution,defocusing and other defects.On the basis of fidelity-based seismic processing,a three-step method for substantial attenuation of the sand dune resonance noise was incorporated.The 3D fre-quency space domain pre-stack random noise suppression technology was adopted to enhance the signal-to-noise ratio(SNR)of pre-stack preprocessing gathers.Furthermore,vertical seismic profile velocity,logging data,and interpreted horizons were combined to enable a multi-information-constrained grid tomography modeling and anisotropic reverse time migration.The results show that the sand dune resonance noise is effectively attenuated,and the SNR of pre-stack seismic data is significantly improved as compared to conventional denoising meth-ods.The residual random seismic noise in pre-stack gathers is effectively suppressed,and the post-processing energy in velocity spectra of the gathers is more focused,facilitating precise velocity model establishment.Based on the high-density seismic imaging gathers,depth-do-main model inversion where the inversion grid is gradually refined from coarse to fine was performed,and the established velocity model can accurately characterize the Ordovician marine reef-beach reservoirs.Anisotropic reverse time migration accurately relocated the com-plex wavefields of the Ordovician marine reef-beach reservoirs,enhancing resolution and focusing.The research results provide a support for optimizing the design of the sidetracking trajectory for Well G1 in the GCD work area,which was validated by actual drilling results.These techniques can provide a robust technical support for high-precision imaging and processing of seismic data in desert areas of the Tarim basin.
NETL
NSTL
万方数据
