The Method Study On Joint Pre-stack Seismic Inversion Of PP And PS Waves

Joint inversion of PP and PS waves is based on the development of multi-wave multi-component. And it uses the information of PP and PS waves which carry the subsurface geology information to obtain highly accurate elastic parameters and reservoir parameters. It can provide geophysical evidence for seismic inversion and reservoir description. Therefore, joint inversion of PP and PS waves can reduce exploration risks and enhance the accuracy of seismic exploration. It is very useful to decrease cost of oil and gas development. This paper studies Pre-stack joint inversion of PP and PS waves from the point view of EI inversion and AVO inversion.Pre-stack inversion uses the information of Amplitude with offset to achieve relative parameters of reservoir character. Rock physics is the bridge of reservoir parameters and seismic reflection character. First, it studied rock physics theory and AVO theory, deducing different PP and PS reflection coefficient approximate equations. And also, it studied the elastic parameters and reservoir parameters’ influence to EI and PS wave EI(PSEI). Then, it introduced the procedure of PS wave processing, including conventional processing, extraction of PS wave angle gather, event registration of PP and PS waves. On the basis of seismic-well tie, AVO forward modelling, it studied the joint post-stack inversion of PP and PS waves. And it tested model data and real seismic data.The paper studied the accuracy of different AVO approximate equations of PP and PS waves. It realized the joint pre-stack AVO inversion of PP and PS waves using the different approximate equations and can achieve the elastic parameters such as, P wave velocity, S wave velocity, density, Young’s modulus, Poisson ratio. Meanwhile, it deduced different formations of EI and PSEI. In the premise of the study, it studied joint elastic impedance inversion of PP and PS waves which used partly angle stacked seismic data to invert EI and PSEI.And it extracted relative parameters such as, P wave impedance, S wave impedance,??, ?? from EI and PSEI. Finally,it deduced the AVOA equation of PP and PS waves in the fundament of anisotropy theory and analysed AVOA features. It can invert the elastic parameters and weak anisotropy parameters of fracture media.