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Digital treating

After the analysis of the held testing and as a result analysis of a fundamental stuff, aprioristic cut-aways ОГТ, ОПВ, ОПП, aprioristic velocity distributions and frequencies the panel of routines has been generated and their optimum arguments are instituted.
The definitive processing graph including routines of assignment of geometry of observations in true co-ordinates of position of posts of excitation and registration, recovery of amplitudes, the peak trimming which has been superficially-co-ordinated deconvolution, subtraction of multiple and particulate-fold waves, interactive police of a statics and kinematics looks as follows:

  • The observation system specification statement 2D the data and geometry check
  • The specification statement of arrangements of sources and recipients on the floor spaces, input of a land forms, depths of holes and zero offset arrival times by means of SPS SPS files and archival tables;;
  •  Calculation of aprioristic static corrections with use of zero offset arrival times and depths of holes (a datum line 0m);;
  • Observation system check;;
  • Input of the seismic data.
  • Reading of the field seismic data in format SEGY and their recalculation in an inner format of a handling complex (FOCUS);
  • Geometry assignment;
  •  Check of assignment of geometry;
  •  Making and archiving of seismograms with the stored geometry in format SEGY with infill of headers;

3. Interactive edition of all seismograms

  • Evaluation test of a seismic data, careful edition of a fundamental data
  • Variation of polarity of traces
  • First break muting

4.  Automatic edition.

  • Muting applay;
  • Removal of peak pressure bumps (harmonisation of amplitudes);;
  • Zero balancing;
  •  Choice of the aprioristic kinematic law in an interactive mode
  •  Imaging of the aprioristic sum a CMP
  •  Amplitudes recovery
  • amplitudes recovery taking into account decay on time (T*N , N=1.4)
  • band-pass filter of 8-14-110-120 Hz
  • Repressing of surface, low-velocity waves-hindrances by means of a complex of programs (LIFT)
  • Manual police of static corrections for Shot and Receivers
  • Audit CMP summation.
  • The maiden stage of interactive police of spread corrections in profile nodal points (through each 2 km taking into account a profile land forms)
  • The second stage of police of static corrections
  • Automatic static corrections by the upper key horizons
  • Audit CMP stack.
  • The surface-co-ordinated adjustment of amlitudes
  • Package from three routines: BALAN-calculation of average value of amplitudes; BALSOL- calculation of balancing coefficients of amplitudes; BALAPP-application of the counted coefficients;
  • Audit CMP stack.
  • surface-co-ordinated, minimum-phase deconvolution
  • Package from two programs: SCAUTO- calculation of the is surface-co-ordinated mean functions of autocorrelation;; SCDECON- application of the is surface-matched operative of the screen to seismic traces. For operation of programs two time windows were set;; ; in the maiden window (50-1600) spacing of prediction GAP=8 msec., white level of noise a window 10%, in the second window (1700-3500) spacing of prediction GAP=8 msec. White level of noise of 5%
  • band-pass filter 8 - 14 –110 -120
  • Audit CMP stack.
  • The second stage of interactive kinematic correction
  • The third stage of static corrections
  • Automatic static corrections on all key horizons
  • Audit CMP stack.
  • Interactive edition of a fundamental data after deconvolution
  • Displacement elimination (DMO)
  • Choice of the partitioning high-speed law for performance of routine of subtraction of multiple waves.
  •  Subtraction of multiple and particulate-fold waves-hindrances (ZMULT)
  •  Audit CMP stack.
  • The third stage of interactive kinematic corrections
  • The fourth stage of static corrections
  • Automatic police of static corrections on all key horizons
  • Audit CMP stack.
  • The fifth stage of automatic police of residual static corrections TRIMST
  • Automatic calculation and application of static corrections on hodographs CMP
  • Definitive summation taking into account TRIMST
  • Definitive norming amplitues to level 2000 with tuning up in a wide window, converting of cut-aways in format SEGY and archiving with assignment of labels.

2.5 Treating of time sections

On definitive cut-aways CMP for the purpose of dilating of a frequency spectrum of a cue, meliorating of the attitude a cue-hindrance, for specification of position of time boundaries special routines have been executed. Treatings:

  • Increase of a proportion a cue-hindrance (FXDEC) (on the sum definitive), normalization of amplitudes to level 2000 with tuning up in a wide window, converting of cut-aways to format SEGY and archiving.
  • Migration of time sections (MIGRATX), amplitudes normalization to level 2000 with tuning up in a wide window, converting of cut-aways to format SEGY and archiving.

2.6 Calculation AVO-attributes

  • Calculation AVO-attributes

With seismograms ОГТ after subtraction of multiple and particulate-fold waves of clutters (ZMULT)  calculation AVO attributes. 
2.7 Features of the method of application of separate stages of treating

Input of the seismic data. At a stage of input of the seismic data for input of profiles of 1981-1982, 1985-1986 g., 1987-1988, 1989-1990, 1990-1992, system XSTAR (produced "Joint-Stock Company development 'Tomsk geophysical trust'"). For input of profiles of 1998-1999 and 1999-2000 SPS-files were used. In the produced system were carried out:

  • Input of the topographic data: a land forms, co-ordinates of sources and recipients, (files of format SRT), tables formings for input to system FOCUS;
  • In processing complex FOCUS version 5.3, at building of tables of geometry detector arrays were described. As a result at this stage of the specification statement of geometry and input of a seismic stuff seismograms in format FOCUS with the pocketed geometry have been received. Further by means of program DATUM automatic calculation of aprioristic static allowances for to a ground of a land forms, depths of holes, zero offset arrival times on a datum line of 0 m. was executed.

Observation system check was executed by two means:

  •  • Interactive calculation and the analysis of profiles of attributes of observation system: the profile of frequency rate, a layout of sources and recipients;
  • • Automatic calculation of a theoretical time-distance curve of primary arrivals (taking into account an electrode geometry and aprioristic static corrections) and its laying on real seismograms in the course of their viewing on the shield. In places of abnormal straddling of idealised and real hodographs the additional analysis of all source data and in need of their police was carried out. The produced operation has been executed on all bulk and has provided 100% conformity check between the described observation system and a seismic stuff.

Repressing of regular clutters on seismograms.
On the produced stuff various phylums of clutters dominate some:
1. Anomalistic peak pressure bumps. For their repressing programs of automatic edition with the task of indispensable proportions of mean and maximum voltages in the set spacings of time windows were used (TFCLEAN, REMSPK).
2. Surface, sound and medium-rate waves-hindrances. The produced phylum meets everywhere. For this clutter characteristicly: intensity of voltage which one many times over exceeds intensity of back waves, unevenness of the form of a cue. The clutter spectrum occupies a frequency range of 8-14 Hz and is a little bridged with a spectrum of a beneficial cue. Surface waves were loosened after application of strip filtering of 8-14-110-120 Hz and programsLFAF. All these routines together with restoration of voltages have been used in one task (a complex of programs LIFT), ), use of a complex of programs is demonstrated in drawing 2.4.
3. Multiple and particulate-fold waves. The produced clutters at sufficient frequency rate are considerably loosened by summation on ОГТ. But for an appraisal of kinematic arguments of gentle reflexes in a Cretaceous and Paleozoic part of a cut-away and increase of a proportion a signal/hindrance on high frequencies multiple waves are necessary for putting away. Routine ZMULT, working in F-K and grounded on subtraction of energy of multiple waves at the introducing of spread corrections, hodographs of usable reflexions leading to a reflattening has been for this purpose applied. Application of the produced routine allows to make singling of horizons more confidently.
In drawings 2.5, 2.6, 2.7, 2.8 high-speed spectrums, summary seismograms before subtraction of multiple waves-hindrances, in drawing 2.9 - pieces of a time section before subtraction of multiple waves are demonstrated.
Adjustment filtering.At the produced stage reduction a seismogram and elimination of influencing of ground conditions the increase problem dared at dynamics of a wave field. The speed key of three routines was for this purpose executed:
The is surface-co-ordinated trimming of voltages (a package of three programs BALAN, BALSOL, BALAPP). The produced routine was applied after attenuation of surface and medium-rate waves-hindrances.
Is surface-co-ordinated, is minimum-phase, predicting deconvolution SCDECON in two time windows with tuning up of the operative of the screen on spacings of target horizons 50-1600 msec. And 1700-3500 msec. The prediction spacing is chosen equal 8 msec., white level of noise of 5%. Calculation of the operative of inverted filter SCAUTO was led taking into account averaging on Shot, software and on OFFSET.
band-pass filtering 8-14-110-120

The example of operation of the program of the is surface-matched trimming of voltages is demonstrated on fig. 2.10. The appraisal of a peak spectrum after adjustment filtering (is surface-matched is minimum-phase predicting deconvolution) is demonstrated on fig. 2.11. It is visible that as a result it was possible to ream a seismogram spectrum essentially.

Summary seismogram CMP


Fig. 2.6. Summary seismogram ОГТ, pieces of a time section with different high-speed curves and a velocity distribution after subtraction of multiple waves-hindrances х


Summary seismogram CMP


Fig. 2.8. Summary seismogram ОГТ, pieces of a time section with different high-speed curves and a velocity distribution after subtraction of multiple waves-hindrances х