Changes

|competition=June 2015

|competition=June 2015

}}

}}

AVO has been a prominent technique in detecting hydrocarbons and reducing drilling risk. AVO can detect hydrocarbons because AVO shows the variation of the amplitude of the offset, which represents the amplitude of the wave energy as it passes through the layer which is influenced by the parameters of the speed and density of the coating, so that the density of the layer can be analyzed by analyzing the reflection coefficient. AVO means that amplitude change with offset caused by lithology of fluid. AVO is also known as AVA (amplitude variation with angle) because this phenomenon is based on the relationship between the reflection coefficient and the angle of incidence. But since the angle of incidence affecting the offset and the offset itself can be varied in order to change the angle of incidence (fig.1), so it is commonly known as AVO.

AVO has been a prominent technique in detecting hydrocarbons and reducing drilling risk. AVO can detect hydrocarbons because AVO shows the variation of the amplitude of the [[offset]], which represents the amplitude of the wave energy as it passes through the layer which is influenced by the parameters of the speed and density of the coating, so that the density of the layer can be analyzed by analyzing the reflection coefficient. AVO means that amplitude change with offset caused by lithology of fluid. AVO is also known as AVA (amplitude variation with angle) because this phenomenon is based on the relationship between the reflection coefficient and the angle of incidence. But since the angle of incidence affecting the offset and the offset itself can be varied in order to change the angle of incidence (fig.1), so it is commonly known as AVO.

[[File:Fig.1.incident angle.png|framed|center|Fig.1.The incident angle is directly proportional to the offset <ref> www.wikiwand.com </ref>]]

[[File:Fig.1.incident angle.png|framed|center|Fig.1.The incident angle is directly proportional to the offset <ref> www.wikiwand.com </ref>]]

==AVO Classification==

==AVO Classification==

In 1989 Rutherford and Williams introduced a three-[[fold]] classification of AVO (amplitude versus offset) characteristics for seismic reflections from the interface between shales and underlying gas sands. The classification scheme they proposed is explicitly defined for gas sands and has become the industry standard; it has proven its validity and usefulness in countless exploration efforts. In 1997 Castagna and Swan proposed AVO crossplotting wherein an estimate of the normal-incidence reflectivity is plotted against a measure of the offset dependent reflectivity. Using this approach Castagna and Swan graphically illustrated the continuum between the classes and defined the characteristics of the classes using what they termed AVO Intercept and AVO Gradient. They also added a class 4 <ref> Young, Roger A. and LoPiccolo, Robert D. (2004). Conforming and Non-conforming Sands – An Organizing Framework for Seismic Rock Properties. </ref>.

In 1989 Rutherford and Williams introduced a three-[[fold]] classification of AVO (amplitude versus offset) characteristics for seismic reflections from the interface between shales and underlying gas sands. The classification scheme they proposed is explicitly defined for gas sands and has become the industry standard; it has proven its validity and usefulness in countless exploration efforts. In 1997 Castagna and Swan proposed AVO crossplotting wherein an estimate of the normal-incidence reflectivity is plotted against a measure of the [[offset]] dependent reflectivity. Using this approach Castagna and Swan graphically illustrated the continuum between the classes and defined the characteristics of the classes using what they termed AVO Intercept and AVO Gradient. They also added a class 4 <ref> Young, Roger A. and LoPiccolo, Robert D. (2004). Conforming and Non-conforming Sands – An Organizing Framework for Seismic Rock Properties. </ref>.

[[File:Fig.4.classification avo.jpg|framed|center|Fig.4. Classifications of AVO <ref>Ahmed,Haseb. Institute of Geologi,University of the punjab </ref>]]

[[File:Fig.4.classification avo.jpg|framed|center|Fig.4. Classifications of AVO <ref>Ahmed,Haseb. Institute of Geologi,University of the punjab </ref>]]