Forward analysis of multicomponent seismic response characteristics in pore-fracture type reservoirs

With the deepening of exploration and development of unconventional oil and gas reservoirs, especially pore-fracture reservoirs with both pore and fracture reservoir structures have become a research hotspot. Due to the complexity of geological conditions and the band limit of seismic data, these reservoirs often show hidden characteristics on longitudinal seismic data, and it is very necessary to carry out multi-wave seismic response analysis of pore-fracture reservoirs. In this paper, we combine the anisotropic fluid substitution theory of Gassmann equation and Thomsen anisotropic parameter theory to carry out equivalent HTI medium petrophysical modeling; use 2.5-dimensional staggered-grid finite-difference method to carry out highly efficient elastic fluctuation orthotropic simulation; and analyze the characteristics and sensitivity of the multi-wave AVO and AVAz responses in a variety of geological conditions. The model characterization shows that the PP wave near-deviation amplitude and PS wave far-deviation amplitude are more sensitive to the changes of fracture density and porosity, which can better reflect the changes of the two parameters; the amplitudes of different offset distances have similar characteristics of the changes with water saturation, and there is a sudden change near 90%; the PP wave AVAz characteristics show that the amplitude amplitude amplitude is near-deviation and far-deviation, and the PS wave shows the opposite trend, and all of them are periodic changes, which can indicate the The PS wave AVAz characteristics show an opposite trend in amplitude, and both of them change periodically, which can indicate the fracture orientation; the defining equation of the PS wave tuned thickness is deduced, which complements the characterization of the multi-wave tuned thickness. The significance of the pore-fracture type reservoir response characteristics to the actual data interpretation is summarized, which provides an important reference for understanding the fluctuation response characteristics of complex pore-fracture reservoirs, helps to understand the actual seismic data phenomena of complex pore-fracture reservoirs, and can effectively assist the design of the interpretation scheme to improve the accuracy of the interpretation.