The Research Of Methods To Estimate Signal-to-noise Ratio Of Seismic Record

Since data processing is used in oil prospecting, People continuously seek suitable method to enhance signal-to-noise ratio full scale. Thus it is more important to estimate the signal-to-noise ratio of the seismic data. In order to estimate quantitatively signal-to-noise ratio, kinds of methods to estimate signal-to-noise ratio arise at the historic moment. Common methods include: stack,related mutual correlation,SVD in time-domain,statistical average analysis,SVD in frequency-domain,estimate in frequency and time shifting correlation method proposing recently.In certain conditions common methods to estimate signal-to-noise ratio can estimate the seismic records that only include random noise. But the seismic data is more complex while seismic survey developing in more difficult area in the west of our country. Once the seismic records contain correlated noise , such as linear noise,ground roll interference,multiples, the common methods estimate worse , even obtain the wrong conclusion that the signal-to-noise ratio before eliminating noise is higher than after eliminating noise. For this reason it is an urgent duty that looking for the method to estimate signal-to-noise ratio of these complex seismic data .For this, the paper preliminary discuss these questions and make some progress.First the paper contrast and appraisal some better methods in estimating signal-to-noise ratio by far: related mutual correlation,estimate in frequency and time shifting correlation method by designing many models, such as level event only contain random noise, inclined event, reflection hyperbola event, single stratum hyperbola event only contain linear noise, single stratum hyperbola event only contain surface wave. It summary their different used scope and condition. On the basis of time shifting correlation method, It develop and proposed a new method to estimate signal-to-noise ratio, In this paper we call it changed time shifting correlation method. It first distinguish correlated noise, then estimate the energy of signal by time shifting correlation, last estimate signal-to-noise ratio.For the method to estimate signal-to-noise ratio in this paper, the paper provide the theory foundation and realization step. Many kinds of theoretic data models designed and real seismic data are used to verify its usability, changed time shifting correlation method have stronger usability, more widely ranges and more real result than other estimate better methods at the present time, in addition this paper discuss its effect factor such as apparent-velocity difference,the energy of signal,the energy of correlated noise and so on, to allow for our use and developing the method.