Research For 2D Joint Inversion Method Of Electric And Seismic Based On The DE Algorithm

The two methods of high density resistivity and shallow seismic french surfacegeophysical field in a wide range of applications in exploration of water,engineering and environment.However,the inversion of single geophysical method in the multi solution problem what has always been a big problem for people.often affevt the exploration result.Secondly,the linearization algorithm of geophysical inversion is also a main reason to affect the inversion accuracy.What throry and practice show is that using the comprehensive geophysical prosecting method to study the establishment of nonlinear joint inversion throry is an effective way to solve the above problems,which is also the hot topics in the research of the theory of geophysical invrsion in currently.Based on the systematic analysis of the high density resistivity method,shallow seismic method and the principle and its modeling throry,a comblination of the two and the first 3D seismic inversion objective function,simultaneous fitting resistivity,elastic wave velocity and medium density inversion,can reduce the solution of a single method the inversion of the more effective.Among them,the high density resistivity method forward to follow the two-dimensional point source model established by Tripp,in the two-dimensional distribution function under the conditions given resistivity,using Fourier transform method,the potential to meet the three-dimensional steady current place of partial differential equation is transformed into two-dimensional wave number parameter for solving partial differential equations,using the finite element method with the into an algebraic equation,the numerical soiution of the wave number domain potential solutions,potential by the Fourier inverse transform method to obtain the spatial domain forward simulation numerical solution;shallow seismic method forward modeling theory based on wave equation theory as the foundation,by using the finite difference method to discretee the equation launched its full waveform,in view of the traditional space two order difference method to simulate the low precision problem,derived the ten order differential equation with boundary conditions,transparent,and the introduction of flux correction technology(FCT)to suppress the numerical dispersion phenomenon,thus effectively improve the full wave forward numerical simulation precision.Secondly,the existing nonlinear inversional algorithm have some shortcomings,on the base of what we introduce the Differential Evolution which is recognized as a better bionic intelligence algorithms of nonlinear algorithm to solvethe electric seismic joint inversion objective function the first time.The algorithm is a heuristic global searchalgorithm,its basic principle is: follow the principle of survival of the fittestin the biological world,intelligent guidance to search the optimal solution in the cooperation and competition among individuals in the population,has strong robustness and parallelism,which can maximize avoid the local optimal solution,beneficial to improve the inversion accuracy.In view of the construction of the 3D seismic inversion theory,we developed that software on the platform of Matlab.Then,we selected the best combination of parameters for the inversion algorithm through the comparison of theoretical model analysis of the results.It had a good inversion results to use the software system to authenticated several typical theoretical models.In addition,the research results for the seismic safety evaluation of a project in HebeiZhangjiakou city project,the high density resistivity method,shallow seismic method for electric seismic joint inversion interpretation,drilling data show that: high density resistance based on differential evolution algorithm is established by rate method and shallow seismic method of nonlinear joint inversion method can effectively reduce or avoid thesolution of the single inversion method,and improves the accuracy of inversion.The research results can provide nonlinear geophysical joint inversion interpretation level,and has important theoretical significance and practical value.