Research Of Post-stack Impedance Inversion And AVA Three-term Simultaneous Inversion Based On Edge Preserving Blocky Constrain

Seismic inversion is a key technique of seismic exploration. Method and algorithm of seimic inversion had been studied in this paper, the seismic datum were Post-stack data and Pre-stack data. Current main seismic methods had been analyzed, a seismic inversion method based edge preserving blocky constrain had been developed, the method’s object is to over the shortcomings of non-uniqueness and nonlinear problem. The nonlinear inversion system equations of post-stack data and pre-stack data had been established by using upper method. To obtain the solution of inversion equations, the conjugate gradient algorithm and simulated annealing algorithm had been studied. Finally, the seismic invesion theory system had been established by using improved conjugate gradient algorithm and divided block model moves across new simulated annealing algorithm based edge preserving blocky constrain idea.Common current seismic inversion methods had been reviewed and classified in this paper. Because the inversion was basted convolution model, the Zoeppritz equation and its approximation equation were introduced and analyzed also, and the suited equation was found for the inversion.In introducing the discrete linear\quasi linear inversion problems and the inverse problem based on probability point of view, a new regularization theory was proposed to solve the problem of seismic inversion. With sparse feature of seismic reflection coefficient, while the reflection coefficient is often not the Gaussian distribution, respectively, the idea of edge preserving blocky constrains was formed. The new inversion was found by adding the potential function into the objective function; finally, inversion theory of protection boundary was formed in seismic impedance (density) model in blocks.Inversion problem is nonlinear, and the number of model parameters is very large, the efficiency of the algorithm is that we must concern. The conjugate gradient method was selected as the local optimization technique, from the standard conjugate gradient algorithm, this paper indruced an algorithm with hybrid form, intended to solve the inversion problem. This paper described the simulated annealing and particle swarm algorithm in global optimization technique aslo.In this paper, post-stack seismic acoustic impedance inversion method and algorithm were studed. Firstly, from the simple linear seismic convolution model, a recursive equation of the conjugate gradient was derived. Due to the non-uniqueness and nonlinear of inverse problems, this chapter derived recursive equation of conjugate gradient solution, solving nonlinear sparse spike inversion.For the absolute seismic impedance inversion, the objective function under the general mixed norm, impedance inversion method and conjugate gradient solution were studied; by using the idea of based on edge preserving blocky constrain, this paper also using logarithmic impedance to describe the reflection coefficient, and firstly, derived nonlinear system equations and conjugate gradient algorithm. The method of inversion has higher resolution.This paper studied three-parameter (P-wave impedance, S-wave impedance and density) simultaneous inversion of the conjugate gradient solution by using prestack seismic AVA data. The forward model is applied to, respectively, the Fatti.AVA convolution model and Hampson convolution model, Hampson convolution model based on statistical relationship exists among P-wave impedance and density, P-wave impedance and S-wave impedance. The introduction of such a relationship in Hampson convolution model, which is of practical significance to the actual inversion, prestack inversion can reduce the non-uniqueness. Based on the idea of edge preserving blocky constrain, firstly, this paper established AVA simultaneous inversion’s nonlinear system equations and recursive equation of conjugate gradient algorithm according to two convolution model.Finally, in view of multi-dimensional and nonlinear of seismic inversion, two kinds of global optimization algorithm were studied, on this basis, a new global optimization algorithm was proposed for seismic inversion. This improved algorithm was called divided block model moves across simulated new annealing algorithm. The new algorithm is proposed to improve in two ways, one is the improvement of the model perturbation formula, which in the model by adding a disturbance term study entry, the learning item to make the move disturbed the function of the optimization; other is the model was divided to many blocks and block moved by the way of cross block in appling the simulated annealing algorithm. By doing this, the algorithm will accelerate the optimal convergenc speed of inversion. Finally, based the idea of edge preserving blocky constrain, the new algorithm was carried out to Post-stack seismic inversion and AVA simultaneous inversion.