METHOD OF ELIMINATING DISTORTION NEAR-SURFACE EFFECTS IN SEISMIC PROSPECTING

摘要

FIELD: physics.;SUBSTANCE: invention relates to data processing in seismic prospecting. A well with depth exceeding the near-surface section power is drilled. When drilling, rock samples, density of which is determined, are taken. A receiver placed on the day surface near the wellhead is used to measure amplitude of direct waves from different sources placed in the well up to the top of high-speed bedrocks of the near-surface section. Damping coefficient of elastic vibrations in the low speed region is determined. Coefficients of reflection and transmission are calculated for the boundaries of the top of bedrocks. The said coefficients, as well as the damping coefficient are used when calculating intensity of direct and multiple waves formed in the low speed region in the interference zone under the top of the bedrocks. The time lag between the time of arrival of multiple waves into the interference zone and the arrival time of direct waves is calculated. A pulse characteristic of the filter F_t is formed, which describes filtering properties of the near-surface section on seismic recording. By applying direct Fourier transformation to F_t, a complex frequency characteristic S_(t) of the corresponding near-surface section filter is calculated. Distortion near-surface effect is eliminated by filtering the observed seismic record using a filter whose frequency characteristic S_(f) ^-1 is an inverse of the S_(f) function.;EFFECT: complete elimination of distortion near-surface effect on seismic prospecting data, increased accuracy of results.;4 dwg