库车坳陷高陡构造地震勘探复杂性定量分析

波与非均匀介质的相互作用是多年来地球物理研究的理论问题之一.本文基于地震成像算子,定量分析了库车坳陷盐相关逆冲推覆构造的复杂性.首先,根据地震资料计算了大北构造、博孜构造、却勒构造、西秋10构造和西秋4构造的速度横向变化非均质谱和地层倾角变化非均质谱,这些量化表征高陡构造地质复杂性的地质非均质谱定最描述了速度横向变化和...

Quantitative analysis of the complexity in seismic exploration of the high and steep structures in Kuqa depression

How a wave interacts with heterogeneous media has been pursued by many geophysicists. Based on seismic imaging operators, we conduct a quantitative assessment of the complexity of salt-related overthrust complex structures in Kuqa depression. We first use seismic data to compute the slowness spectrum and the dipping-angle spectrum for the Dabei, Bozi, Quele, Xiqiu 10, and Xiqiu 4 structures, respectively. These heterogeneity spectra express the geological complexity of subsurface structures as a spectrum to quantify lateral velocity variations and dipping-angle distributions. Through an interaction between the geological heterogeneity spectra and the migrator's angular spectra, we obtain imaging efficiencies and complexity coefficients for these complex structures in Kuqa depression, which quantitatively evaluate the geological complexity in terms of migrators. The results indicate that the Quele-Xiqiu structure zone is more complex than the Dabei-Bozi structure zone. Along Quele through Xiqiu 10 to Xiqiu 4, the complexity coefficient gradually increases because of stronger velocity contrasts, broader heterogeneity spectra, richer off-peak spectral contents in the slowness and dipping-angle spectra. These conclude that time migrations for complex Kuqa structures are prone to cause wrong imaging and migration noise. Depth migrations should be enhanced for Kuqa depression.