| In the actual work area the underground conditions are complex and changeable.The existence of strong reflecting surface leads to the development of multiples.Multiples interfere with primaries in the seismic section,reduce the resolution,and interfere with the migration accuracy.According to the position of the interfaces which generate multiples,we can divide multiples into internal multiples and free surface multiples.The suppression technology of free surface multiples has been relatively mature,but the suppression of internal multiples is still a problem.Now the requirements of the exploration accuracy continue to increase.It is an important problem in seismic data processing to suppress internal multiples efficiently and accurately.In this paper the method of suppressing internal multiples is studied based on the existing research results.Firstly,this paper analyzes the properties of multiples,tests the suppression effect of conventional methods,and studies the generation factors and physical properties of internal multiples.In terms of kinematics,geometry and dynamics,this paper provides a theoretical basis for multiple suppression.Then,according to the formula of inverse scattering series,the prediction formula of internal multiples is deduced.The prediction formula is simplified by using the constraint conditions.This saves the calculation cost and time.Then this paper chooses a blind separation of convolution signal method to carry out adaptive filtering for subtracting the predicted multiples adaptively from the original data.The adaptive subtraction method can preserve primaries effectively while suppressing the internal multiples.Under the condition without the velocity model,the inverse scattering series method in this paper can predict the internal multiples in the simple horizontal model,a basin model and the actual data.The adaptive subtraction method in this paper can suppress the internal multiples effectively.The model test and the actual data test verify the validity and practicability of this method.At the same time,a software interface is designed based on the method in this paper.It can be used to process actual data. |
