1. n. [Geology]

The angle between the vertical projection of a line of interest onto a horizontal surface and true north or magnetic north measured in a horizontal plane, typically measured clockwise from north.

See: attitude,  dip,  strike,  trend

2. n. [Drilling]

The compass direction of a directional survey or of the wellbore as planned or measured by a directional survey. The azimuth is usually specified in degrees with respect to the geographic or magnetic north pole.

See: directional drilling,  inclination,  survey

3. n. [Reservoir Characterization]

The angle that characterizes a direction or vector relative to a reference direction (usually True North) on a horizontal plane. The azimuth is usually quoted in degrees from 0 to 359.

4. n. [Drilling, Shale Gas]

The direction in which a deviated or horizontal well is drilled relative to magnetic north. Most horizontal wells in shale reservoirs are drilled in the direction of the minimum horizontal stress. This allows for the creation of multiple hydraulic fractures that are normal to the wellbore.