Elastic Characteristics of Fault Damage Zones Within Superdeep Carbonates in Northwest China

This chapter investigates the internal architecture of fault damage zones using seismic attributes of curvatures based on 3D seismic reflection data from superdeep carbonate reservoirs in northwest China. Our results show that there are three typical fault damage models and their geometrical attributes including main directions and fracture density are characterized using statistical methods. We study seismic parameters (e.g., anisotropy and attenuation) relevant to elastic scaling down fault damage models under different frequencies using finite-element modeling. The equivalent stiffness tensors of the three models are significantly affected by frequency. Comparing the three models at the same seismic frequency, the stiffness coefficients are mainly controlled by their densities. We also discuss frequency-dependent seismic attenuation of the three fault damage models and found out that their maximum attenuation appeared at the same frequency, while the different values are affected by directions orientations of the impermeable fault cores. This work quantitatively appraises interpret the complex fault damage zones and highlights the importance and usefulness of combining the methods of seismic, rock physics, and geology to characterize their attributes.