By Colin Rice
Drill rods and drill pipe are an extremely expensive part of the drilling operation and so correct break in and maintenance procedures are essential for long life.
This is the fourth article of Part 3 of our Technical Series on Drill Rod Safety. Click here for an outline of the entire Technical Series on Drill Rod Safety.
The following care and maintenance instructions have been extracted from the drill rod manual published by one of our Contributors, MBI Drilling Products. Click here for detailed tips on how to properly look after drill rods.
Break-in procedure for new MBI drill rods
The life and efficiency of a wireline drill rod is often determined during the first few make-ups of the threaded connection. If care is taken at this time, the chances of an extended life will be greatly enhanced. A few simple checks during the first few make-ups will ensure that thread performance is improved and drill rod life is maximised:
1. All MBI drill rods are shipped with a light coating of thread compound on both the pin and box threads, this is provided to prevent corrosion and also to prevent galling during the first make-up of the thread. It is critical that this coating is not removed before use.
2. At the first make-up of a joint ensure that the pin and box are properly aligned and avoid stabbing damage when lowering the pin into the box. Ensure that the joint is not cross-threaded.
3. Make up the joint as tightly as possible by hand.
4. Once the joint has been made up as far as possible by hand, check that the stand-off is within specification, 1.5 - 3mm (0.059’’ – 0.118’’). If the stand-off is greater than 5mm break-out the joint and check that there is no debris or other foreign matter interfering with the joint. If satisfied that the joint is free of foreign matter re-align the connections and again make up by hand.
5. Fully make-up the connection by applying the specified pre-torque to the connection.
6. Once the joint has been fully made up to the specified pre-torque level again check that the stand-off gap is fully closed and run the drill rod into the borehole.
Care and maintenance of MBI wireline drill rods
1. After every rod trip ensure that all threaded ends are completely clean. Inspect each threaded end for indications of cracks or other surface damage and if found remove the drill rod from service.
2. Before re-running the drill rod ensure that each threaded end has a light coating of a good quality thread grease. The importance of the use of good quality thread grease cannot be over emphasised – failure to use thread grease will lead to accelerated thread damage and galling.
3. Do not mix drill rods from other manufacturers with MBI drill rods and do not use adaptors manufactured by other manufacturers with MBI wireline drill rods. Use only MBI manufactured adaptors at the waterswivel and hoist plug. All MBI adaptors are manufactured to the same exacting quality as our drill rods and so the end user can be assured that the integrity of these critical connections is not compromised.
5. Wireline drill rods are very thin walled care must therefore be exercised when handling wireline drill rods to ensure that the threaded ends are not damaged in any way during use, through stabbing, or during loading or off-loading. Any damaged drill rods should be immediately removed from service.