The Investigation Of The Evaluation Of Seismic Record And The System Development

With the developing of seismic surveying, the seismic data acquisition gradually extend to the areas which have complicated geologic conditions both on the surface and in the subterranean, usually in this kind of area the data's S/N ratio is very low. Because many traditional techniques are not being improved accordingly, the whole survey level was limited, one of the problems is that there is not a completed QC systems.Now it's necessary to develop a completed QC system that can analyze the seismic data quantitatively. Improving seismic surveying level, the fundamental thing is to improve the mass of single shot record. Qualitative evaluation and controlling the mass of single shot acquisition in field are the urgent topics at present. The paper's objection is to improve the locale evaluation speed of seismic data, including from removing noise principle to operator realization, from picking first break to envelope contour computer automatic identification, from system of locale evaluation development to practice and application, investigating how to filter with effect, first break picking accurate, fast operator realization, software system developing and so on. To filter with effect, several principles and operators of removing noises are compared and studied. The primary task of data processing is to improve S/N ratio of data, however, accurate processing will reduce operation speed. Locale processing is mainly to give a preliminary evaluation of field seismic data. Consequently, there is a confliction between pursing high S/N ratio and improving locale evaluation speed. The system sacrifices some S/N ratio properly for improving the processing speed to satisfy the requirement of locale evaluation. On the study of seismic first break, in order to fit the requirements of locale evaluation, it is needed to find a method that can assure accuracy and improve the speed of computation. This method according to the theory of simulate reflect fractal, auto detect seismic first arrivals by computing the Hausdorff dimensions of seismic time sequence. The improved arithmetic of fractal dimension not only reduces much computation, but also improves reliability and stability of the results, and the results independent of the accuracy of interpolate. On the software developing of field evaluation system, it consider adequately on the function of man-machine interact, analyze various factors that may be found in seismic surveying, the items of evaluations have options, the evaluation standard have revisability, it can divide seismic records into three grades, as first, second and waster, then evaluate the quality of original records, output various pictures such as frequency compose, major frequency, focus frequency, energy, S/N ratio and resolving power curve, and also can output files that content first arrival datum, abnormal traces and Excel note, all of this can satisfy the needs of field seismic evaluate on speed. The study has some innovative points: 1. The field evaluation system has been developed. 2. We can evaluate seismic data timely and automatically by filtering seismic data, optimizing arithmetic. So it has extensive application in realities. 3. The computers can evaluate seismic record automatically, so we can reduce factitious factors, make the results fair, improve the efficiency of fieldwork and reduce cost.