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Processing of time sections and migration transform. For amplification of the useful signal and pinch of a relation a signal-hindrance, on gained after application of a correcting statics on hodographs CMP to definitive time sections, program FXDECON. has been applied. Then the band-pass filtration of a spectrum in different temporary windows (FILTER(spectrum)). has been applied. After that sections were exposed to migration procedure (2D Finite-difference exact migration MIGRATX), after has been applied definitive normalization amplitudes to level 2000 with adjustment in a wide window. On fig. 2.15 fragments of definitive time section CMP at a final stage of processing (the total definitive, FXDECON, migration, FXDECON and amplitude norm) are shown.

Fragments of time section CMP at stages special processings

 

a) CMP stack                             b) FXDECON by Stack                    c) Migration
Finished                             Finished                         (FXDECON+MIGRATX)
Fig. 2.15 Fragments of time section CMP on a lateral view 991725 at stages special processings.

Calculation  AVO attributes.   AVO attributes have been calculated on seismograms CMP after subtraction of the multiple and partially-fold waves of noises. The used procedures of processing have allowed to maintain a relation of amplitudes depending on removal.
For slices produce AVO of attributes seismograms CMP have been conversed to seismograms on lines of equal angles of indicence from 00 to 36 with a step 6.
On fig. 2.16. On the right it is figured seismograms CMP from which it is gained seismograms on lines of equal angles of indicence of the beam, presented at the left in the same drawing.
In drawings from 2.21 till fragments of sections of the totals on equal angular samples:
00 -70:60-120; 90-150; 120-180; 150-210; 180-240; 210-270; 240-300; 270-330; 300-360 on a lateral view 991712. We see that distinction of the totals at small change of an angle of indicence inappreciablly, but the odds in sections at small angles of indicence and at major behaviour of boundaries of reflexion are visually appreciable.
After calculation angular sample sections for everyone a lateral view have been gained, the representing all signals registered on lateral views with angles of indicence 70 (in a window ±50) and 300 (in a window ±50) and are gained sections of differences of these totals. Anomalies of a discrepancy of values of amplitudes in a slit of differences can be related with hydrocarbon for this parent these sections have been gained. In drawing 2.17 for angles of indicence 70 and 300 (in a window ±50) two sections on a lateral view 991712 are presented. We see distinction these 2 sections among themselves and it allows to see distinction of energy of reflexions from the same horizons at angles of indicence 300 and 70. In drawing 2.18 are presented a difference of the totals at an angle of indicence 300 and an angle of indicence 70 and definitive net slit CMP.
On seismograms angular selection have been calculated:

  • Reflectivities (AVO-attribute) since they are one of diagnostic signs of rocks;;
  • Poisson's ratios  (AVO-attribute) allow theoretically substantiated to approach to the forecast lithology the tank, to petrophysics to performances of the tank and to the forecast of change of character of a saturation;;
  • gradient  G (AVO-attribute);
  • intercept - R0 (AVO-attribute).

Gradient - G  related to the elastic parameters under certain conditions. When a significant change in attitude Vp/ Vs gradient-G  has the raised value on a demarcation and can serve as a good exponent of presence of gas in porous breeds.
Intercept-R0   Characterises a surface reflexion power.

On a lateral view 991712 fragments of sections gradient gradient - G and intercept - R0  and intercept - R0 in drawing 2.19, and fragments of sections of Poisson's ratios and reflectivities in drawing 2.20 are presented.

AVO

 

           angle of incidence 70        angle of incidence  170   angle of incidence 270
                    Seismogram after processing
                 Fig. 2.16 at the left seismogram AVO, gained on lines of equal angles of indicence, on the right seismogramme after DMO and ZMULT with the entered kinematics and a staticsй

Section fragment at angular slope 300 and 70

 

Section fragment at angular slope 300 and 70
Fig. 2.17 Fragments of sections of the totals at angular slope 300 and 70 on a lateral view 991712

Fragment of a difference of the totals and definitive slit CMP

 

Fragment of a difference of the totals and definitive slit CMP

             Fig. 2.18 Fragments of sections of a difference of the totals of sections at angular slope 300 and 70 and definitive time section CMPТ

Fragments of sections AVO

 

gradient-G (AVO-attribute)                         intercept – R0  (AVO-attribute)

Fig. 2.19 Fragments of sections AVO – attributes gradient-G and   intercept – R0

Fragment of a slit of Poisson's ratios reflectivities

 

Fragments of slits of Poisson's ratios       reflectivities

Fig. 2.20 Fragments of slits of Poisson's ratios and reflectivities

Section fragment at an angle of indicence 6-12 and 0-7

 

Section fragment at an angle of indicence 6-12 and 0-7

                            Fig. 2.21 Fragments of slits at angles of indicence 6-12 and 0-7(AVO-attributes)

Section fragment at an angle of indicence 12-18   and   9-15

 

Section fragment at an angle of indicence 12-18 and 9-15 

            Fig. 2.22    Section fragment at an angle of indicence 12-18   and   9-15