Owners and operators of horizontal directional drilling (HDD) tools recognize the importance of keeping their tooling in top condition. Well-maintained HDD tools perform better, are more productive and are less likely to fail.
Obviously, with directional drilling tools, the biggest issue is wear and tear. The more difficult the conditions, and the longer it is used, the risk of failure increases. Failures during pullback can occur in many places on the drill string, but the root cause can sometimes be traced back to the reamer. That’s why we recommend a three-step approach to manage your reamer fleet.
Inspect Your Directional Drilling Reamer
This sounds like a simple task but inspecting the reamer after each use —and before the next — is critical to a successful pullback. The extra effort can prevent the HDD tool from being lost downhole. After every bore, the reamer should be completely washed and flushed internally with clean water. This will improve inspection but also clean out mud or additives that can dry out and clog fluid ports.
Once cleaned, check for wear or cracks on the shaft, which can form around the threaded ends and along the shaft. Box connections can flare, while pin threads show early signs of wear or cracks. The area where the shaft meets the reamer body is another point that should be inspected for excessive wear. Make a note not just of missing teeth or carbide cutters, but of any damage to remaining cutters. Carbide cutters rate two to three times harder than the heat-treated shaft and base metal of the reamer body, without the carbide, damage to the tool escalates quickly.
A “hole opener” with roller cone cutters is a good example of a tool that will need more care and maintenance than a traditional reamer. Beyond the normal checklist mentioned above, you will also need to pay close attention to the bearings, cone and shirt tail (or gauge protection).
Rotating each cone will help remove residue and flush the bearings. Sealed bearing cones will turn sluggishly but with some rigidity. Seals will decline and spin slightly more freely than new cones. This doesn’t mean the cone is in bad shape, it just needs more attention with some maintenance. If you find it rocking or movement, you will likely need to replace it.
Maintain Your Directional Drilling Reamer
A little bit of upkeep goes a long way. Take time to replace all missing, cracked and heavily worn cutters. The placement of cutting teeth and carbide is designed to work as a “system.” Missing cutters increase the torque load on adjacent teeth or other areas of the tool which can reduce the effectiveness of the ream as well as jeopardize the entire HDD bore.
Smaller cracks on the body can be ground and welded, while any larger or deeper cracks might suggest major repairs and replacing the reamer. Remove thread grease and replace it with new, not only to ease connection and disconnection but also to protect the thread from oxidation and rust.
Clean and grease the swivel after every bore. It’s always best to store reamers under a roof, shed or a waterproof cover, if possible.
Repair Your Reamer
Create uptime out of downtime. Whether the contractor performs the repair in-house or sends it out, it is a good idea to use downtime to make repairs to your reamer fleet. A few helpful tips to consider when making repairs or maintaining your reamers. Mind the diameter. Not only the OD of the tool but to the centerline. Tools repaired “out of round” can cause problems. Consider using adapter subs to minimize the wear on the shaft threads – subs are much easier and cheaper to replace.
Replace or apply additional hard facing to areas showing signs of wear.
Like carbide, hard facing is a significantly harder substance than the body material of all reamers and is effective at prolonging the life of a reamer. It can be applied by stick welding, MIG, and OA torch and most contracts already rely on this discipline. If you don’t, it is worth considering.
Always use thread protectors. The bed of a truck or trailer is an equally violent environment.
Often HDD reamers are used, sprayed off, and dropped in the yard for future bores. If left too long, rust, dirt, rain and erosion will limit their usability – return on investment. More and more drilling contractors are recognizing the value of a simple maintenance plan for drilling tools.
To sum it up,
- Inspect: Thorough inspection after every bore is critical. Make it part of the job. No question, today’s contracts have busy schedules, but like oil changes to the company truck, this effort will add value in the long run.
- Maintain: Thorough cleaning, flushing, and greasing go a very long way. Keeping all HDD tools in a dry-covered area will prolong the life considerably. Consider assigning a dedicated person to mind the health of your reamer fleet.
- Repair: Whether you perform repairs yourself or send them out, it is a good idea to dedicate a period of downtime to get them completed. The value of this effort is having your fleet of reamers ready to go when needed instead of rolling the dice the day of the next drill.
Directional Drilling contractors have a ton of tasks to juggle — and in today’s economic climate everything needs to go right to make a healthy margin. Maximizing the usefulness of all tooling is one area that can improve the bottom line.
Of the directional drillers who contributed to this article, all are optimistic about the amount of trenchless work in the year ahead. They also agree, however, the challenge lies in getting the work done profitably.