Study On Signal Consistent Processing Methods In Stack-array And Time Lapse Seismic

To match the precision of seismic exploration, lots of processing methods have been put forward. But this can't satisfy the demands of subtle geological explanation of complex fault block. Single point high density data should be put in use to improve processing precision. With development of oil and gas exploration technology and development level, many oil fields have been found and developed continuously. So looking for remained oil and enhancing oil recovery is becoming more and more important. Time lapse seismic which is the seismic means applied to monitor the development of oil field, has becoming a hot topic in recent years.According to the development and present situation of high precision seismic exploration and time lapse seismic, and research of signal inconsistency effect on stack-array and time lapse seismic, in this paper, the following researches are specifically presented. Firstly, we summarize the affecting factor of signal inconsistency from acquisition and processing and so on, and analyze the array effect in many cases elaborately. Secondly, we illustrate the basic principle of signal consistent processing from time correct, amplitude equalization, matched-filtering and phase correction, and introduce equalization technology and the advanced methods. Theory model was used to analyze the problem of conventional matched-filtering and show the advantages of the improved method. Morphing technique in image processing is introduced into the equalization of time lapse seismic to eliminate time-shift effect coupling with amplitude differences, and amplitude differences become noticeable. So difference section can reflect the changes of fluid in reservoir correctly. Consistent array tests of modeling data were taken on the basis of methods research.Model tests indicated that consistent array can solve the problem of high frequency attenuation caused by conventional array, enhance the similarity between traces and broaden spectra range. And the effect of relief surface and irregular layer on stack-array was weakened by consistent array. Then consistent array tests were taken on real high density data. Compared to conventional array, surface wave and random noise weakened, effective wave strengthened relatively with consistent array. The research shows that high frequency components were protected, and the signal to noise ratio was improved without affecting the resolution via consistent array.Signal consistent processing method was applied to time lapse seismic and realize cross equalization. Via model tests, we analyzed fluid change reflected by difference response of time lapse seismic data. Then non-repeatable time lapse seismic data were obtained by changing parameters. And cross equalization effective was good by applying consistent processing method. In this paper, cross equalization tests have also done on real time lapse seismic data. And the processing flow was formed to improve repeatability of the data. The processing results of theory models and real data verified the feasibility and effectiveness of the method. Time lapse seismic data processed by cross equalization can reflect the dynamic change of fluid more precisely.