GYR-OR assemblies may be utilised where it is necessary to orientate directional drilling assemblies or other down hole tools such as whipstocks or perforating guns.

Gyro orientation is performed on an e-line unit so that orientation data can be displayed in real time at the surface. Gyro orientations are generally performed in shallow near vertical drill holes where the presence of steel casing precludes the use of magnetic tools, or in deeper drill holes where magnetic formations are the source of interference.

The gyro tool-face is referenced to a known direction such as true north or sighted along a know survey baseline at surface and a muleshoe is attached to and aligned with the gyro assembly. In addition an orientation device is placed just above the directional assembly into which the muleshoe seats when the GYR-OR assembly is run into the well. The coupling of the muleshoe and orientation device ensures that the gyro tool face alignment is transferred to the directional assembly allowing it to be orientated from the surface.

APPLICATIONS:

The most common applications are:

• Accurate delineation of drill path - free from magnetic interference
• Cased hole / in-rod surveying applications
• Whipstock / DHM and other kickoff orientations 

ADVANTAGES:

• accurate and reliable
• not affected by magnetic interference from drill pipe or magnetic rock formations
• lengthy field calibrations are not required prior to each survey
• drill collar azimuth does not need to be pre-determined
• no need to gyro-compass each survey in vertical drill holes, therefore quick operation