The Study And Application Of Pre-stack Seismic Elastic Parameters Inversion Based On Zoeppritz Equation

With the further development of petroleum exploration,exploration target is moving from structural reservoirs to complex reservoirs.Exploration technology based on structural reservoirs is no longer suitable for complex reservoirs.It is necessary to propose some new technologies.Pre-stack inversion can obtain the elastic parameters of underground rocks,which can provide reliable basis for complex reservoirs exploration.Pre-stack inversion depends greatly on the approximation formulas of Zoeppritz equation.These approximation formulas are valid under certain assumptions,which restrict their application range.Firstly,this paper deduces the partial derivatives matrix of P-wave reflection coefficient to three parameters(v_p,v_s and?),compares the accuracy and stability of precise equation and approximation equation,and establishes the frame of pre-stack inversion based on generalized linear inversion.Secondly,this paper introduces two kinds of prior distributions(Gaussian distribution and Cauchy distribution)and builds two target functions of pre-stack inversion based on Zoeppritz equation.Then,1D models and 2D model are built to analyze the result of these two methods and the method with Gaussian prior distribution is strongly model-based,while the method with Cauchy prior distribution does not.Finally,apply the inversion with Cauchy prior distribution to the study area of the East China Sea basin.And the fluid detection is also fulfilled by three parameters inversion and rock physics statistics.The result shows that this method achieved good effect.