Seismic Structure Interpretation Of Longmen Shan Foreland Thrust Belt Based On Wave Equation Forward Modeling

It contains rich petroleum resource in Foreland thrust belt, which is an important area of current oil and gas exploration area of China. But the complex underground structure and surface condition of thrust belt usually result to poor quality of seismic exploration data. So the seismic interpretation may exist variable solutions. Seismic forward modeling is an effective tool of understanding complex structure characteristics of the seismic wave field, and it can improve the accuracy of interpretation from the angle of seismic data interpretation. Forward modeling results may help in identifying Thrust Belt wave field characteristics and distribution.This thesis mainly talked about the following four aspects, from the perspective of seismic data interpretation.Firstly, the tectonic style is analyzed in the north area of Longmen Shan foreland thrust belt. The widely developed regional tectonic style of this area is the basis of model structure construction.Secondly, the model is established based on analysis of structural styles and comprehensive geological information. Structural model build on both regional geological structure style and seismic data interpretation. Meanwhile, velocity model is based on pre-stack time migration profile. The velocity filled before well check and then the forward model is completed. At last, it's necessary to verify model legitimacy through the balanced cross section, geophysical data and seismic forward modeling techniques.Then, Numerical forward modeling experiment is carried out on the basis of the seismic data of Longmen Shan foreland thrust belt. Zhongba area is an example area of this forward modeling experiment. After data processing the modeling, it turns out that Kirchhoff pre-stack time migration can be used to comparative analysis of complex seismic wave field effectively.Finally, it achieved perfect application effects that seismic modeling and pre-stack time migration. Through comparative analysis between the wave group characteristics of modeling results and the actual profile, we optimized structural interpretation solution three to one. Pre-stack time migration results show the same pattern configuration of mode explanation, details will also have a significant impact on the imaging results.Above all, it provide a reliable structure interpretation model to conduct forward modeling of seismic wave field for the complex structure area, especially for foreland basin thrust belts. And it also achieved perfect application in the Longmen Shan foreland thrust belt, which provide support for oil and gas exploration of Sichuan basin.