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Processing procedure

According to the geological assignment processing of seismic materials is spent in the full dynamic gamut (format R4), in a wide frequency band (8-120 Hz) with restoration of amplitudes. A processing time interval 0-4000ms, a step of digitization 2 ms.
There was a task in view, to gain effect with the qualitative relation a signal/hindrance in a wide frequency band and to provide inconvertible correlation of reflexions cretaceous and Jurassic slit parts.
In the beginning of processing of the area testing of key parametres of procedures of processing for the purpose of a select of their optimum values has been yielded. Parametres of restoration of the amplitudes, is superficial-co-ordinated deconvolution on seismogrammes, a band-pass filtration at various stages of processing, procedure of impairment of the regular noises, procedures of migration of a temporary slit were exposed to testing. Testing was spent for the materials registered on different seismic stations and different field batches, quality and which geological situation were an average for all area, and was carried out by search of parametres in a restricted gamut with an estimate of quality of effect. The chosen parametres have been fixed for all material. In the course of processing after each stage comparison of the gained effects with previous was carried out and on the basis of the relative measure of quality the solution on transition to a following stage of processing or recurring flowing with other parametres was made. Thus changes of parametres should not lead to waist of a strip of spatial and temporary frequencies and to change of the shape of the useful signal. The visual analysis of effects was supplemented with comparison of the quantitative parametres calculated by an identical fashion: the gain-frequency spectral characteristics of a signal and noises.
For the purpose of obtaining of qualitative temporary sections in addition to standard procedures of processing the programs were used, allowing to refine quality of a primary material, and accordingly, also sections CMP. The complex of programs LIFT, LIFT which allows to eliminate peak emissions has been used, to ooze a signal against noises at embodying of a special processing graph. Advantage of the given complex is possibility of noise elimination without application of procedures importing the considerable amplitude distortions (such for example as FK filtration).
The band-pass filtration has been chosen 8-14-110-120 Hz. Testing of an interval of a prediction deconvolution has been held. As the seismic material was

registered on different seismic stations and at various times, the solution was accepted that for processing, will be chosen is superficial-co-ordinated deconvolution (SCDECON) c by an interval of a prediction 8 msec. The band-pass filtration has been chosen 8-14-110-120 Hz. On total CMP we have applied procedure DMO to elimination of effect of a seismic pulling down and correct performance of migratory transformation on primary seismogrammes ( shots). The effect of operation of program DMO on primary seismogrammes is visible on fig. 2.3. Examples of application of software package GAIN+FILVTX and software package LIFT on initial seismogrammes are given in drawing 2.4. The effect of application of a complex of programs LIFT. is well visible. This complex has been used in the course of processing. .

Example of program result DMO

 

a) Seismogramme to DMO                               b) seismogramme after DMO
Fig. 2.3 Example of operation of program DMO on seismogrammesм

GAIN+AMPSCAL+LFAF+TFCLEAN+FILTER

 

a) Initial seismogramme b) Seismogramme after c) Seismogramme after
  Applications of programs Applications of programs
  GAIN+FILTER LIFT

Fig. 2.4 Examples of operation of complexes of programs GAIN+FILTER and LIFT

(GAIN+AMPSCAL+LFAF+TFCLEAN+FILTER)