Orientation sub used in HDD industry as MWD instrument. A sensor is fitted in the back plate of the sub and used for measuring while drilling. The size of orentation sub is customized as per the size of sensor. An orientation sub is a downhole tool used in the oil and gas industry to measure the direction and orientation of the borehole during drilling operations. It is also known as a survey tool or directional sensor sub.

The orientation sub typically contains a series of sensors that are used to measure the inclination, azimuth, and magnetic direction of the borehole. The data collected by the sensors is transmitted to the surface through a wireline or telemetry system, which allows drill operators to monitor and adjust the direction and trajectory of the borehole as needed.

The orientation sub is an essential tool in directional drilling, which is the process of intentionally drilling a wellbore in a specific direction or trajectory to reach a target zone. By measuring the direction and orientation of the borehole, drill operators can make adjustments to the drilling process to ensure that the wellbore is drilled in the desired direction and trajectory.

Overall, the orientation sub plays a critical role in the success of directional drilling operations, as it allows drill operators to accurately and efficiently steer the wellbore to its intended target.