## 3D Seismic Geometries

# Fully Sampled 3D Geometry

A full sampled 3D is where the sources and receivers are evenly spread on a grid where the receiver and source interval is equal to the receiver and source line intervals. It is the ideal 3D geometry we would all use if cost were not a consideration.

# Orthogonal 3D Geometry

An Orthogonal geometry is where the source and receiver lines are placed orthogonal to one another with the line intervals being larger than the station intervals.

# Megabin 3D Geometry (Parallel)

A Megabin geometry has the source and receiver points on the same line with all lines running parallel. The source interval is typically a factor of the receiver interval.

# Slant 3D Geometry (26.565 degrees)

A Slant geometry has receivers lines at an acute angle (<90 degrees) to the source lines. Two of the most angles used in Slant surveys are 26.565-degrees and 45-degrees. The angle represents the azimuthal difference between source and receiver lines.

A 26.565-degree angle between source and receiver lines will result in the sources being shifted ½ the source interval crossline from the previous source.

# Slant 3D Geometry (45 degrees)

The second common 3D Slant geometry involves a 45-degree angle between source and receiver lines. The 45-degree angle results in a crossline shift of 1 SI from the previous source point.

# Brick 3D Geometry (standard)

The standard Brick geometry has the source line between alternating receiver lines shifted by half the SLI to produce a standard brick pattern.

# Brick 3D Geometry (triple)

The triple brick is a variation on the standard brick where the source line is split into 3 alternating offsets between receiver lines with each offset being 1/3 of the SLI.

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