AVO Attribute Extraction

AVO Analysis can be used as a reconnaissance tool to look for AVO anomalies and decide the appropriate approach to quantitative reservoir characterization.

Attribute Extraction and Analysis

Using AVO Analysis for reconnaissance followed by the appropriate inversion technique is an efficient way to find and characterize prospects within any seismic survey.

AVO Analysis

AVO effects on pre-stack CMP gathers provide basic information on the lithology and fluids in the reservoir rocks in your field. AVO Attribute Extraction works with the other Jason® Workbench applications, allowing you to do a better job of integrating traditional seismic AVO analysis and Jason seismic inversion.

AVO analysis helps in the prediction of reservoir characteristics away from well control points. Reliable estimation of petrophysical parameters is needed as input for such studies. These petrophysical estimates are an integral part of advanced reservoir characterization and modeling. CGG GeoSoftware also offers PowerLog® and Rock Physics Module (RPM), a set of integrated petrophysics and rock physics applications that support the petrophysical modeling needed for robust AVO analyses.

AVO classes; Avset et al., (2005)

Creating synthetic offset gathers using well logs and petroelastic parameters from PowerLog RPM indicates what kinds of AVO anomalies may be present in the data. This is done with Jason WellTie using synthetic wavelets.With the Estimate Wavelets extension to WellTie, the specific wavelet from the seismic data can be used for even more accurate modeling.

AVO Analysis Example

At right is a cross plot of the intercept versus gradient (Shuey 2-term) extracted along a horizon on the section shown below, color coded with time.

AVO crossplot of the intercept versus gradient (Shuey 2-term) extracted along a horizon on the section shown below, color coded with time.

A number of points diverge from the trend, indicating a Class-I AVO anomaly.

What this means in terms of rock properties is purely qualitative. However, when looking at a simultaneous inversion result, (the bottom two panels of the section view below) the reason is clear: The Vp/Vs in the layer above the horizon changes dramatically across the anticline.

AVO Section View: The Vp/Vs in the layer above the horizon changes dramatically across the anticline.

Detect Amplitude Anomalies

Starting with NMO-corrected gathers, you can use AVO Analysis to make a first pass scan to detect amplitude anomalies, as well as make an estimation of the contrast of the seismic and elastic properties of the rocks.

The following attributes are offered:

  • Intercept and gradient (Shuey 2-term)
  • Intercept, gradient and far offset (Shuey 3-term)
  • Vp and Vs contrast (Smith & Gidlow)
  • Zp and Zs contrast (Fatti et. al)
  • Bulk- and Shear – modulus and density contrast (Cray et. al).

Mute, taper, stabilization, and filter functions are included to ensure robust results.

Input NMO gathers and Shuey 2-term intercept and gradient results. Background color is the P-Velocity trend used for angle-offset conversions.

To learn more about this innovative tool to advance your AVO projects and tailor workflows, go to our Free Software Evaluation Form to test drive AVO Attribute Extraction, or  Email us to learn more.

GeoSoftware - Jason

Jason

Advanced technology in seismic inversion and reservoir characterization. Optimize well productivity, field development and reservoir management.
GeoSoftware - Software Support

Software Support

Our team of experts have years of collective experience in geoscience software. Find the resources you need to answer your questions. Visit our support portal to get the help you need.
GeoSoftware Support - Contact Support

Contact Support

Get support phone numbers and email addresses for your geographic region. Request software download credentials and assistance with setting up user ID/password. Our 300 experts in 17 countries stand ready to serve you.