In seismic attributes, we have two types of attributes which are surface attributes and volume attributes. These attributes are used to enhance the visualization of the data and also aid in data interpretation. 

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1. Surface Attributes 

 

1. Root Mean Square (RMS) Amplitude attributes

      The Root Mean Square (RMS) or quadratic mean, is a popular magnitude of variation over a       dataset. 

•  The RMS is useful when the values run through positive and negative domain like in seismic traces.

• It emphasizes the variations the varitions of acoustic impedance over a selected interval 

•  The attributes is use on the surface of the horizons 

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2. Volume Attributes 

 

1. Coherence (Variance)

• Variance attributes is calculated in 3D

• It represents trace to trace variability over a particular sample interval and therefore produces interpretable lateral changes in acoustic impedance. 

• This attributes is applied on smooth 3D seismic data.

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 2. Local structural Dip

• This attributes is the estimation of local dip from seismic data

• It is used to compute other seismic attributes in respects the orientation field of the seismic reflectors. 

 

 3. Local structural Azimuth 

• This attributes is applied on smooth 3D seismic data also.

• This attributes is used to estimate the local azimuth of the seismic events. 

• The attributes is viewed in all three slices; inline, crossline and timeslice.

 

 4. Dip Deviation 

• Dip deviation takes into account the difference between the dip trend and the instantaneous dip.

• By tracking rapid changes in the orientation field, edges, and subtle truncations become visible.

• This edge attributes has been found to work successfully for the low-angle fault illumination.

•  It is applied to the whole 3D seismic data.

 

 5. Structural Smoothing 

• We applied structural smoothing is to increase the continuity of the seismic reflectors.

• We use this together with the principal component of dip and azimuth to determine the local structure followed by structural smoothing. 

 

 6. Curvature

• Curvature is a 2D property of a curve and describes how bent a curve is at a particular point on the curve

• For a particular point on a curve, its curvature is defined as the rate of change of direction of a curve.

• In comparison to variance, the 3D curvature volumes (in the image below Directional curvature) can highlight areas that are not easily discernable on variance.

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 7. Sweetness

• Sweetness is a relatively new (first described by Radovich and Oliveros, 1998) attribute used in 3D seismic interpretation and visualisation is appropriately named ‘Sweetness’. 

• Sweetness is an attribute designed to identify “sweet spots” places that are oil and gas prone and improves the imaging of relatively coarse-grained (sand) intervals or bodies.

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8. Amplitude Versus Offset (AVO) 

• ​ AVO is to determine a rock’s fluid content, porosity, density or seismic velocity, shear wave information, fluid indicators (hydrocarbon indications)

• advantage of being applicable to many conventional seismic data sets without the requirements of prohibitive acquisition, processing, and analysis costs

• Anomalously low Vp/Vs ratios caused by hydrocarbons produce anomalous AVO response. However, Vp/Vs ratios can not be uniquely inverted from AVO data alone

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9. Envelope

Envelope attributes also show reflection to strong acoustic impedance contrast. It is measured from complex trace of seismic signal used to locate significance seismic features. for instance, lithology variation, faults and discontinuities. Gas and sand layer will give response to envelop attributes as bright spot in corresponding to acoustic impedance changes.

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