Seismic Scattered Wave Field Propagation Characteristic And Forward Modeling For The Inhomogeneous Media

With the development of seismic exploration, the simple structured reservoir which easy to exploit can no longer satisfy the growing requirement for oil and gas resources. Now exploration and development have focused on complex non-homogeneous reservoir. So people pay more and more attention to the seismic scattered wave suiting for the inhomogeneous media. Furthermore, heterogeneity is always associated with more geologic structure, oil and gas and ore resource. Therefore, it is widely and practicably valuable to study seismic scattering theory in complex heterogeneous medium.Main research contents and conclusions in the article are following.1. We have built seismic scattered wave field through analyzing principle of the scattered wave. Scattering of seismic wave field can be simplified with Born approximation or the Rytov approximation. Simulate the seismic scattered field by using integration method based on Green's function. The forescattered and backscattered filed were separately calculated by downgoing and upgoing Green's function.2. Using mathematical analyzes the gradual process from the generalized scattering to narrow. Analyzing similarities and differences of the scattered wave and the reflected wave, then verify the Fresnel zone radius is the reference point between scattered wave and diffraction wave.3. In order to get the seismic scattered field of the multi-scale heterogeneous structures such as fractures system, multi-scale mesh generation and variable grid integration method are introduced. With the multi-scale mesh generation and variable grid integration method, we will have a good description the scattered wave characteristics of lean cracks and large angle scattering body. In this paper, an example lean cracks, investigate the relationship between speed, density, aspect ratio, inclination, position of lean cracks and scattered wave characteristics.4. We investigate the cave resolution based on seismic amplitude with seismic scattered wave field forward modeling. Meanwhile, we made a summary of the conditions of the"string"phenomenon.5. After numerical simulation to the scattered wave field of actual model contains pored media, recognize and analysis the characteristic of heterogeneous media, validate the applicability and portability of the Green's function integration numerical method.