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What is a drill collar? What are the classifications?

release time：2023-12-04

source： network

The drill collar is located at the bottom of the drill string and is the main component of the lower drilling tool assembly. Manufacturing using AISI4145H chromium molybdenum bonded steel by rolling or forging, effectively controlling the chemical composition and trace element content. Its main feature is a large wall thickness (generally 38-53mm, equivalent to 4-6 times the wall thickness of the drill pipe), with a high gravity and stiffness

Drill collars are divided into: ordinary drill collars, spiral drill collars, non-magnetic drill collars, short drill collars, and drill collars with slip grooves.

Non magnetic drill collar action

Why is it necessary to use non magnetic drill rods or non magnetic drill collars when using MWD in oil drilling, rather than ordinary drill collars or pressure bearing drill rods？

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Non magnetic drill collar action

Why is it necessary to use non magnetic drill rods or non magnetic drill collars when using MWD in oil drilling, rather than ordinary drill collars or pressure bearing drill rods？

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