Research And Application Of Dipole Matching Pursuit In Seismic Inversion

Seismic inversion,as a means of seismic exploration,has been widely used.Impedance information is one of the important links between geologic and geophysical connections.Therefore,wave impedance inversion is a common method used in seismic inversion methods.It is a special seismic processing technique that uses seismic data to invert formation wave impedance.Matching pursuit impedance inversion has attracted much attention as a more commonly used inversion method in recent years.However,the current matching pursuit inversion method is inefficient and the resolution needs to be improved.Therefore,it is particularly necessary to improve and develop high-precision matching pursuit inversion techniques.This paper first summarizes the development history of wave impedance inversion,and introduces the development of impedance inversion in different periods from two aspects abroad and home.Secondly,the principle of matching pursuit algorithm is studied.The principle of matching pursuit algorithm is to find an atom that is best matched with a given signal in an overcomplete atomic dictionary by building an overcomplete atomic dictionary.Finally,a series of optimal atomic combinations is instead of a given signal,so as to achieve the purpose of improving the resolution.After introducing the theory of decomposition of dipole,dipole matching pursuit is introduced on the basis of the matching pursuit theory.Because of the atoms in the dictionary by single reflection coefficient into double reflection coefficient,therefore the dipole matching pursuit algorithm can achieve higher precision of the sparse decomposition of seismic signal,which is applied to identify thin layer.Although traditional dipole matching pursuit inversion can improve the resolution to a certain degree,there is still room for improvement.In this paper,we mainly improve the two core problems of dipole matching pursuit algorithm: the establishment of odd and even atomic dictionaries and the setting of threshold value.Through research,we set the two layers of reflection coefficient in seismic signal interval maximum as odd and even atoms in the dictionary the limit value of reflection coefficient,in this way,both can guarantee redundancy of atomic dictionary,also reduces unnecessary matching process,and improve the computational efficiency.In the meantime,we use the residual and the number of matches as the threshold at the same time,as long as one of the conditions is satisfied and the matching is finished.In this way,the threshold value can be set to minimize the number of matches,and the matching effect can be achieved to the best.Through the model test,the improved dipole matching pursuit algorithm can improve the resolution and improve the operation efficiency.Finally this paper uses the seismic data of a working area in the south China sea to perform the path integral inversion to obtain the relative wave impedance.Comparing with traditional dipole matching tracking results,it is found that the results obtained using the improved inversion method are better in lateral continuity and can have good correspondence with the well data,demonstrating that the improved dipole matching pursuit method is suitable for practical data processing and which can achieve better application results and provide an effective basis for realizing high-precision reservoir prediction.