Drill Rod Maintenance and Proper Use Shouldn't Be Overlooked

Take time to use the drill rig and components correctly and you will have an easier time directional drilling.
Drill Rod Maintenance and Proper Use Shouldn't Be Overlooked

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As a series of moving parts under constant pressure, your drill rod undergoes continual wear and tear every time you put it to work. Horizontal directional drilling tooling is built to withstand extreme stress, but careless use can cause your drill string to malfunction prematurely.

Proper care and attention will ensure that you get the longest life possible out of your equipment.

STEERING IS STRESSFUL

The biggest stress on your drill rod is the fact that it’s frequently rotating at 100-300 rpm and often being forced through the ground at an angle. Constant rotation, plus the bending action applied during steering, increases the fatiguing stress on your drill string and strains the steel rods at their connection points.

As you push your HDD tooling to the max, you might make the drill shot, but you won’t realize that you’ve damaged the rod until your next shot. Worse yet, your pipe could simply snap while down in the hole, costing you valuable time, money and manpower before you can continue.

What You Can Do: Don’t push your drill rod through severe bends. If you need to make a compact curve or ease around a tight corner, it’s better to drill halfway, extract your equipment from the hole, and then approach from the opposite angle. This lightens the burden on your directional drilling tools because you’re tackling an angle that is only half as tight.

GOING TOO FAST

Attempting to steer too quickly means that you’ll likely apply too much thrust. This can easily overpower your directional drilling tools. Your drill rod is strong enough to withstand the thrust of your rig, but encountering an unexpected solid mass or harder material while drilling at full speed can cause you to damage your equipment and stall your job.

What You Can Do: Take your time, and do the job carefully. Don’t simply try to muscle your way through by increasing fluid pressure or rotation speed. Pay attention to changes in resistance on your equipment and hydraulic pressure gauges. Ease through blockages slowly. Swap out drill bits if necessary.

LOOSE PIPE ASSEMBLY

One common mistake seen is when the drill pipe is not torqued up correctly because it’s assumed that the drill pipe can be torqued up downhole. In fact, the drill pipe might not tighten to the necessary specs at all, especially in soft ground. When your drill pipe isn’t “made-up” the way it should be, the threads must absorb the torque. When properly tightened, the torque will go through the shoulders of the connections, achieving maximum strength.

What You Can Do: Once again, take your time. Use your rig to correctly torque your drill pipe. Keep an eye on the process as you go, and never try to save time by assuming that everything will tighten up downhole.

THREAD ISSUES

As drill pipe is assembled and disassembled, the threads on the pipe ends experience constant wear. This is especially problematic when two pipe ends are misaligned and the error isn’t caught. Over time, this misalignment creates excessive wear, or even thread galling. This will cause not only a loss of torsional strength, but can potentially strip out the thread entirely.

It’s also important to avoid mixing new drill pipe with old drill pipe. Intermixing worn pipes with perfectly-machined, fresh pipes can cause the new ones to prematurely wear down to match the misshapen threads. If threads are worn enough, the pipe won’t tighten correctly at all and you’ll lose a lot of strength straight out of the gate.

And let’s not forget the saver-sub up at the drill carriage. This little guy touches each and every drill pipe. If this thread gets messed up or too worn, it will be reflected in all your drill string threads. Check it often, always grease it, and replace as needed.

What You Can Do: Take the time to use your rig to torque your drill pipe correctly. If you absolutely must mix old pipe with new pipe, keep old and new together as much as possible so fewer old and new threads are mated.

Also, be sure to rotate your “lead pipe” (the first pipe connected to the tooling). It’s easy to continually reuse the bottom pipe in the basket as the first pipe connected, but this is the one that gets most stressed out. Swap out this pipe regularly with others in the drill string to prevent premature failure and a potentially expensive loss of tooling.

Your HDD tooling is powerful, but not indestructible. As with any heavy equipment, proper maintenance and refusal to cut corners will preserve the integrity of your directional drilling tools and ensure they achieve their maximum life span. To talk about how to better maintain and protect your equipment, contact your local HDD distributor.

ABOUT THE AUTHOR

Peter Melsheimer is the marketing director at Melfred Borzall. While the bulk of his time is spent creating marketing plans, Melsheimer fills in wherever needed. He has been in the HDD industry since 1989 and by 1991 was out demonstrating and educating the world about the advantages of HDD for utility installation. His formal education is in mechanical engineering, but he has gained years of expertise in marketing learned on the job.



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