
Drill Collars
Steel and Non-Magnetic Drill Collars
Introduction
When magnetic surveys are required, a non-magnetic drill collar is essential to obtain accurate survey results.
DTI’s non-mag collars do the same structural job as conventional collars, without distorting the magnetic field around your directional survey instruments. They run with standard drill string tools and stabilizers and are manufactured to API Spec 7-1.
Choose from four configurations. Slick collars come in standard OD and 29 to 33 ft lengths. Flex collars have a reduced body diameter for added flexibility. Spiral collars have a spiral groove cut into the body to reduce the risk of differential sticking. Pony collars come in 10, 15 and 20 ft lengths. Every collar has a shot-peened bore for added resistance to stress corrosion cracking. For more demanding wells, materials with a higher PREN are available on request.
Corrosion Options on Request
Shot-peened bores as standard, with higher-PREN materials available when your well calls for them.
Drop-In Compatible
Runs with standard drill string tools and stabilizers, no special handling or adaptation required.
Built to API Spec 7-1
Manufactured to API Spec 7-1, with mechanical properties verified to ASTM A370.
How It Works
Strength Without the Signature
Directional surveys depend on magnetometers reading the earth's field without interference. Interference from steel drill string components can throw those readings off course. The location of the well and orientation to the North Pole can alter the amount of magnetic interference.
Non-magnetic collars replace the steel around the survey instruments with non-mag material that carries the same loads without creating magnetic interference. Depending on the location, the amount of non-magnetic collars can vary. DTI provides the variety of options in sizes and configurations needed to address these challenges in most applications across the globe.
The result is a BHA that delivers weight, length, stiffness or flexibility where it's needed, with survey readings the directional driller can trust.

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