Amplitude-preserved Processing Based On Bifocal Version Of Common Focus Point Technology And Its Parallelization

With the development of gas and oil exploration and exploitation, lithologic interpretations are in the great need. In order to efficiently provide interpretations more precise amplitude-reserved section, we studied amplitude-preserved processing based on bifocal version of CFP technology and its parallelization. After the study of amplitude-preserved processing based on bifocal version of CFP technology using conventional ray theory, we pointed out amplitude-reserved processing based on bifocal version of CFP technology using wave equation wave field extrapolation theory. Parallelization of those two methods is presented in this paper for promoting the computation efficiency. We also developed a GUI for the wide use of these methods.During the study of amplitude-preserved processing based on bifocal version of CFP technology using ray theory, in the first focusing step, by using the method of the finite difference to compute the travaltime, using the principle of equal time and the analysis of differential time shift, we studied the computation of the reversed-time focusing operator, the computation of synthetic CFP gather, the position identification of CFP response and the evaluation of correct focus operator. We combined traveltime and amplitude together to make the amplitude of operator meet the feature of wave field propagation. We used the principle of stationary phase and the stack of Fresnel band to promote the resolution and signal noise ratio of CFP gather. In the second focusing step, using the principle of convolution and correlation, grid point gathers are generated. We got reflection coefficient functions by using the Radon transformation. Ultimately we realized amplitude-preserved migration and the analysis of CFP-AVP based on ray theory.During the study of amplitude-preserved processing based on bifocal version of CFP technology using wave equation wave field extrapolation, we realized a half wave equation and full wave equation processing flow. We fully considered the influences of wave front diffusion, geological condition, designed the amplitude-preserved operator which can eliminate the effect of receivers and propagation. We improved FFD extrapolation operator to compensate the amplitude difference generated by geometry diffusion loss. In those two processing, we used DTS panel analysis to update the operator and the velocity field, which we can get the correct velocity model and garentee the correct imaging result. Tests using model data and field data, and CFP-AVP analysis all proved the validity and practicality of amplitude-preserved processing method based on bifocal version of CFP technology.The computational efficiency of amplitude-preserved processing based on bifocal version of CFP technology is a big problem which can prevent the imaging method from widely use to the industry. According to the principle of parallelization, and using MPI scheme, we designed and realized two parallel algorithms. One is data parallel algorithm, the other is master-slave parallel algorithm based on check points. We improved the computational efficiency by applying them to amplitude-reserved processing based on bifocal version of CFP technology.A seismic data processing system based on CFP technology has been developed based on Linux operating system, combining a cross-platform C++ graphical user interface library Qt, using mixed programming languages including C/C++ and FORTRAN, the multi-tread technology, OOP (Object-Oriented Programming) thinking, etc. This will also provide a solution for the development of other seismic data processing software. We tested it using model data and field data, and get good results.