The Research Of Seismic Forward Modeling Method For The Inhomogeneous Media

The petroleum exploration development to today, Complicated unconventional oil andgas reservoir has been paid more and more attention. Oil and gas resources are rich incomplex structure area, namely the strong tectonic area. This region of the heterogeneity isvery strong, cracks, caves and pore are abundance. Scattering theory has fast speed, highstability and high s/n ratio for the simulation and processing complex medium of small scale.Simulation of the seismic response characteristics of complex heterogeneous body usingscattering theory, plays an important role in oil and gas resources exploration. This papermainly studies the following aspects:We introduce the process of establishing the wave equation’s integration solution usingthe Green’s function. Application Born approximation, thin-slab approximation and one way’sGreen function establish single scattering wave’s propagation operator. We us the method ofinterpolation to achieve forward modeling with grid variation, and discuss the absorptioneffect of attenuation boundary condition.The paper studies deeply the fracture-cave heterogeneous body, especially the seismicresponse characteristics of the fracture, System analysis heterogeneous body’s relationsbetween parameters and response of small scale. Take the advantage of Green’s function, weforward model the three-dimensional heterogeneous model with cracks and caves. Andmigration imaging. Verify the importance of the three-dimensional forward and migration forunconventional oil and gas reservoirs. Analyse the orientation response characteristics ofvertical fracture, including travel time, amplitude and orientation angle.Based on the theory of wave equation’s differential method, we forward modelingheterogeneous body containing small scale fracture using finite difference method, compared and analyzed the result with forward simulation using Green’s integral method which basedon the scattering theory. We points out the integral method and differential method in theforward modeling small scale body on their advantages and disadvantages. In order to makethe finite difference method can meet the crack of high multiple variable grid simulationrequirements, we developed a multi-stage variable-grid finite difference method, which notonly guarantees the precision, and improves the efficiency of simulation.