Our non-magnetic drill collars are supplied with an “as rolled” surface finish condition. All non-magnetic collars are hot cold worked in order to provide them with the necessary mechanical and magnetic properties. The bars are then trepanned, hot spot inspected and machined. An internal bore treatment is performed on the full length in order to achieve the proper compressive status of the internal diameter. This provides the collar with optimal resistance to stress corrosion cracking. All of our drill collars are manufactured in accordance with API spec 7, Q1 and recommended practice 7G, as applicable.
Here at EBIC Oilfield Equipment Co.,Ltd. we know not every project is the same, therefore requiring a variety of collars. All of our drill collars can be customized to suit your specific requirements by adding some of the features listed below.
Standard Drill Collar Features & Options
- API pin stress relief groove and box boreback
An API pin stress relief can be used on all drill collars and downhole tools. It is a recommended option in situations where fatigue can occur as a result of bending. By removing any unengaged threads in the high stress areas of the drill collar connection, it is less likely to crack due to fatigue because the bending will take place in the area of the connection with smooth surfaces that are free of stress concentrations.
- Internal bore treatment
This option generates a compression level of at least 60,000 PSI at a given depth.This provides the collar with an excellent resistance to stress corrosion cracking.
Three optional spiral grooves can be placed on the outer diameter of the collar to allow the mud to circulate freely around the drill collar. This is to equalize the pressure as well as to prevent a seal forming. This will help reduce any chances of differential sticking.
An optional outside profile can be machined to reduce the collar rigidity if required.
- Elevator and slip recesses
Optional slip and elevator recesses are available to improve handling and safety.
These two features can be used together or separately. These options are cut as per API recommended practice 7G.