Field acquisition,
processing and interpretation
of VSP data.

VSP Training Course and Workshop Illustrated by processing of real VSP data
By Dr. A.Tabakov

This course will be given for all comers in day of arrival GR2013.
The cost of a course is 8000 rub for each participant.


Vertical Seismic Prospecting – origination and development (E.I. Galperin)

  • History of VSP origination
  • VSP as bridge between logs and surface seismic
    /Logging by downgoing waves, primary reflections, true signature for surface seismic, time to depth for surface seismic, anisotropy from VSP/
  • VSP as method of prospecting the near borehole space.
    /Offset VSP, Walkaway VSP, 3D VSP/
  • VSP as third dimension in seismic prospecting (2D + VSP, 3D + VSP)

Field acquisition

  • Down hole geophones
    /Pressure and temperature resistance clamping, resonances, inclination resistance, polarity, right hand configuration, frequency band, dynamic range, digitizing, transmission/.
  • Acquisition 1D, 2D, 3D and 2D + VSP, 3D + VSP geometries
    /Downhole and auxiliary channels, stacking, visual control, operators report/
  • Signature, time and amplitude control.
    /Reference geophone, geometry and special notes/.
  • Depth control.
    /Cable depth, registration, control acquisition/.
  • Quality control.
    /Signal to noise ratio in different frequency bands/.


Processing


Preprocessing
  • Description of well and acquisition geometry, headering
  • Editing of frequency resonances and amplitude spikes.
  • Static corrections from reference geophone
  • Signature and amplitude corrections from reference geophone.

First break peaking

  • Direct peaking and correlation.
  • Determination and subtraction of correlated noises before first breaks
  • First break peaking under complicated conditions /Modules XYZ, Modules XY, Low frequencies/

Polarisation and orientation.

  • Local, geographic, PRT and SP-oriented XYZ coordinate system;
  • Polarization parameters.
  • Orientation;

Static corrections

  • Principles of static corrections
  • Static corrections for SP from model joint optimization;
  • Static corrections by smoothing of hodograph;
  • Static corrections from symmetry of downgoing and upgoing waves;

Velocity models

  • Interval, layer and average velocities from VSP, vertical hodograph;
  • Calibration of sonic log;
  • Layering of logs;
  • Combining of VSP and sonic log models;
  • Anisotropy (TLA);
  • Anisotropy : transversly isotropic media Geometries of models;
  • Joint optimization for several SP;

Wave field analysis.

  • Elements of wavefields:
    P, S, PS down going and upgoing waves;
    Tube waves;
    Sideway waves;
    Vibrations of uncemented casing;
    Surface waves;
    Waveguide back dispersion;
    Frequency resonances;
    Amplitude spikes;
    Random noises;
    Gas discharges;
  • Principle of additive iterative subtraction analysis.
  • Polycor correlation of waves.
  • Determination and subtraction of waves
    2D Fourier filtering;
    Polycor weighting;
    Sliding base determination and subtraction along hodograph combining Fourier filtering and Polycor weighting.

Deconvolution

  • Prediction error statistical deconvolution
  • Prediction error and spike signature deconvolution
  • Surface seismic to VSP deconvolution

Migration

  • Ray migration
  • Kinghoffer migration
  • Finite difference migration

Inversion

  • Inversion of reflectivity
  • Inversion of sections
  • Full vector inversion

Anisotropy study

  • Tranversal isotropic media with horizontal axis of symmetry
  • Tranversal isotropic media with vertical axis of symmetry
  • Splitting of shear waves
  • Study of fast to slow waves

Wavefield modeling

  • Reflectivity modeling
  • Wavefield equation
  • Mathematical modeling
  • Ray method
  • Finite difference modeling

Interpretation and presentation of results

  • VSP to log matching
  • VSP to surface seismic matching
  • Traditional interpretation of 2D and 3D VSP
  • Anisotropy estimates.

Contacts
43, Zaitseva st., room 263, Saint Petersburg, 198188, Russia
Phone:
+7 (495) 754-9990
+7 (903) 255-7275
+7 (911) 236-7708
e-mail:
vsp@geovers.com
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