Drill collars are an integral heavy duty joint that are constructed from a solid bar of AISI 4145H modified alloy steel. Our standard drill collars are supplied with an “as rolled” surface finish condition.
All standard bars receive heat-treatment that provides them with the necessary mechanical properties. The bars are then trepanned and drifted.
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 job is the same, therefore requiring a wide 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.
- Phosphate coating
All threaded connections can be treated with a phosphate coating to help prevent threads from galling.
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.
Optional hardbanding is available in various materials. Drill collar hardbanding
is normally applied flush to the outside diameter of the bar. Other configurations are available upon request.
- 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.