Abstract:Erroneous field observation system is often found in seismic data processing, and it causes very bad result, In order to avoid repetitive seismic exploration and improve data processing result, the author compiled the program which uses first break to check and correct field observation system on IBM 3081 computer. Two correction methods are outlined. The first method only corrects offsets. It includes the following gist: (1)one or several quite accurate first-break time distance curves which are used as standard curves can be plotted by analysing short-refraction data, uphole time values, reflection data, etc. in an area; (2)a real first-break curve from common-shot gather is compared with the standard first-break time distance curve to determine offsets corresponding to the real first-break curve and to revise the space property of each seismic trace. The processing result of the 3D seismic data collected from an area proves the method highly effective. The second method first calculates the coordinates of shotpoints and geophone stations by applying iterative method with the addition of error limiting condition, then estimates offsets and finally makes correction. The correction effect of this method is also obvious. It is experimentally shown, however, that instead of calculating coordinates, we make offset correction to achieve partial correction for the seismic data in which there is major observation system error. An appropriate correction method should be chosen according to the properties of seismic.