AVO (Amplitude versus offset )
AVO
Amplitude versus offset or amplitude variation with offset is a variation in seismic reflection
amplitude with change in distance between shot point and receiver.
The most important application of AVO is the detection of hydrocarbon reservoirs; rising AVO is
typically pronounced in oil-bearing sediments, and even more so in gas-bearing sediments.

AV0 analysis is aimed at understanding the full range of physical properties of the rocks and fluids
that may be present in the subsurface. Rather than starting with an observed AVO anomaly and
generating a discrete earth model that matches and using this to evaluate risk, we start by looking
at the geology and the trending of rock properties and establish correlation using uncertainty.
Forward modeling of these physical properties produces a range of possible seismic amplitude
responses. Only by comparing the observed anomaly with these realizations built from our rock
properties and correlations knowledge can the stochastic amplitude anomaly be correctly
evaluated.

To evaluate a prospect we must know how closely the AVO matches the expected response for oil
or gas and how closely it matches brine or other lithologic responses that could mislead the
interpreter.
These methods are offered as stand-alone products or as part of integrated studies involving
Integrated Quantitative Interpretation methodology.
Preferred Acquisition Parameters

  • Designed for high pre-stack S/N
  • Large dynamic range (noise suppression)
  • High bandwidth
  • Small spatial sampling increment
  • Consistent source signature
  • Wide aperture for imaging
  • Wide angle distribution
  • Azimuth distribution (wide or narrow?)
  • Short arrays or point sources and receivers
    (omnidirectional)
  • Regular geometry – minimize pre-stack footprint
  • Consistency of distributions – fold, offset coverage,
    azimuths
  • High effective fold (within the mute range)
AVO product for one prospect,  after bandpass filtering and amplitude scaling.