How Do You Steer a Drill Below The Earth?

When the commotion of construction must be minimized, try horizontal directional drilling!

Like laparoscopic surgery for the earth, horizontal directional drilling (or HDD) doesn’t require digging open a large area like a shaft or a bore pit to get started. Instead, the drill can plunge directly into the earth’s surface. From there, horizontal directional drilling is pretty straightforward, but it’s not necessarily straight. In fact, HDD necessarily uses a curved alignment to enter the earth, travel below a roadway or river, and exit at the surface on the other side.

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This is not engineering advice. Everything here is for informational and entertainment purposes only. Contact an engineer licensed to practice in your area if you need professional advice or services. All non-licensed clips used for fair use commentary, criticism, and educational purposes.

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This video is sponsored by Nebula.
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Tonic and Energy by Elexive is licensed under a Creative Commons Attribution License
Producer/Writer/Host: Grady Hillhouse
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Intern: Myles Jonas

[dcviper]

I work in the fiber optic network industry, and previously worked in the gas utility industry. We used to joke that you should always carry a length of fiber optic cable with you in case you get stuck on a deserted island. Just bury the cable and when the guy with the backhoe comes out to cut it you can just ride back with him.

[vipahman]

That string in the gel demo was awesome and gave such a simple and precise explanation of a problem that I always wondered about. Beautiful!

[DonDuracell]

Here in Germany that drilling method did become more known to the public when the company "FlowTex" was sued for the (back then) most expensive large-scale fraud in Germany. The damage was roughly 4.2 billion USD.

The company had 270 machines but those were sold multiple times (3142 machines had been sold).
When they had investors visiting they drove to one drilling site, then had lunch and then drove to a different drilling site. During the lunch brake they moved the drills from site 1 to site 2 creating the illusion of a bigger pool of machines. (see my correction)

*Correction*
The scam worked more like that they changed the serial number plates on existing machines with new created serial number plates.

[uk_steve]

I used to work for a UK drilling company as a tracker. We drilled under railway lines with mm tolerances on the tracks. Under woods that had preservation orders and under lots of domestic properties. We drilled under a river aiming for a range rod that the client had stuck in the ground. I will never forget the look on his face when we emerged from the ground and knocked the rod over.
We used to say " any fool can still down. Coming back up and arriving where you want to be takes skill.

[MrAzcatfan]

As a utility locator, The talk about the potential impacting of other underground utilities was greatly appreciated. Always call before you dig!

[__shifty]

used to work on a directional drilling crew. very cool. we were a small company and one day we hit a big set of fiberoptic lines. poor company went bankrupt after paying for repairs on that fiber.

[buadel]

4:50 bentonite needs hours of mixing to shear so it creates the shear-thinning fluid it needs to be able able to suspend cutting while pump is off. Posting this comment while my drilling bit is drilling at 14, 000 ft below ground. I always liked the way u demonstrate concept and really liked how u showed how mud supports well walls.. one more thing is also when water infiltrate in permeable sand leaving solids on wells wall which supports it which we call filter cake. Ty for ur quality content and good presentation. Glad i found something to relate to in ur channel.

[hankschannel]

Thanks Grady! This answered so many questions that I didn’t even know I had. We had one of these drill right through the water supply to our house. They were like, “there isn’t a pipe here” and I was like, “well, there’s no water going into our house anymore so…”

They had it all patched up in a couple days.

[alexkirkendall]

I worked installing fiber optic cable when I was in high school, horizontal drilling 4’ underground in residential areas. I was the guy who used a hydrovac to expose existing utilities before drilling so you didn’t hit them with the bit.

I then got a degree in petroleum engineering and work in the oil and gas industry drilling horizontal wells. The concept is identical and many technologies are shared, only difference is you start going horizontal at 10, 000’ instead of 4’!!

[pyotrberia]

I could never have imagined how you can steer a long, flexible drill bit. After you explained it, it seems so obvious.

[vennic]

Having recently experienced fiberoptic cable installation in my neighborhood, I can confidently say the lack of trenching was both noted and appreciated

[cmdr]

I assisted an HDD on Mariner East 2, ME2. We had an inadvertent return so bad we built a pit around it and simply used it as a recirculation pit. There was a lot of effort to mitigate damage professional geologists at each drill and field techs/engineers walking the surface to look for IR's. Amazing tech

[dakotaflowers]

My hone region of ohio is known as "DD paradise" because there are 50 or so directional drilling companies based in a 20 Sq mile area. Also 4 years ago, TC Energy did a reconstruction project on the east buckeye express 36in diameter natural gas pipeline which travels underneath 3 major waterways in my region. My favorite way to kill time was to go out and watch the semi sized drilling rigs boring and pulling up to 3 miles of pre-bent thick wall pipeline on the ROW.

[Jwalker]

I work at an Engineering firm and have designed multiple directional drills across intercoastal waterways. I now use this video to introduce new engineers to the basics of directional drill. Thanks for putting this together. Also, I see you used to work for Freese, we are partnered with them on a project. I'm a Kimley-Horn guy.

[Gunnutmm]

I studied geology and worked with directionally drillers at a utility contractor. Their biggest challenge the drilling foreman told me was hitting hard rock at glancing angles. The problem project that eventually had to be trenched was at the foot of the Wasatch mountains and they hit a high quartz content sedimentary layer less than 30 degrees from parallel to it and it just skipped along the outside edge of that fold and came out where they didn't want it to. They had drilled right through it at more square angles where the bit would be forced to go ahead and chew through that harder to cut rock.

[nobody]

They use pulsed mud systems sometimes for locational information. We used to do maintenance on downhole tools, and one we had was a probe that was powered by a turbine spun by the mud going down the drillshaft. it sent information back to the headunit by limiting the mudflow, causing pressure pulses upstream.

More useful than radio when you're 20kft or more deep. Measured all kinds of information. Radiation, vibrations, temperatures, gyro orientation, magnetic fields. All useful for figuring out where and what you're drilling through when you can't see it.

Oh also tangentially related (no pun intended), the drill bits on the end, are also powered by that same mudflow. It's quite ingenious use of an already required aspect of drilling to add a power transfer through the lubrication medium. It's like if the coolant pump on your CNC mill actually powered the computer and the spindle at the same time.

[WhoDatBoudreaux]

Great video, as usual. I splice fiber for a living. My work depends on HDD crews followed by pedestal/hand hole installer crews to get their jobs done before the fiber blowing crews can put the fiber cable in.

Something not mentioned here (which I think is very important for the public to know) is the importance of "call before you dig". Our HDD crews have to put in locate service requests 72 hrs before they start. Any company with utilities/pipes/fiber/gas has 72 hours to mark the requested route with spray paint or flags. If they DO NOT MARK IT, the repair cost is their burden when it gets hit.

There is a huge misconception that HDD crews are always careless when they are drilling. Many times, other companies have not properly grounded their systems, used tracer wire in non-conductive pipes, or adequately documented where their pipes are... their buried utilities can't be definitively located.

One job just up the road from me has broken the water main so many times because the city claims they don't have the equipment, manpower, or budget to do the locate requests and mark where the water main goes... Even though the primary contractor offered to give them the equipment and pay an overtime rate for all city employees needed to complete the task. In the end, they hit the water main 3 times a week and they are portrayed as the bad guys.

For those wondering... hitting a 288 fiber cable and damaging a 1000' section can run well over $15, 000 in fiber splicing cost alone. I don't know the HDD costs or any of the other expenses needed to replace the cable... But it is very expensive to break a fiber cable.

[erikig]

I drove by these crews in Broward for months and didn’t get what they were up to and why it was taking so long.

It is so easy to get frustrated with the delays they kept causing 😅, thanks for helping me understand the complexity of what was going on.

[derekfordyce]

I once wrote a guidance program for a pneumatic directional drill head. It allowed for horizontal and vertical profiles, and I had to invent a method for aligning two vectors in space using at most 2 curves with a minimum radius of curvature (it involves normal vectors to planes and an iterative approach). The drill head was one of a kind, with no mud required and an average speed of 1 foot a minute. The contract fell apart though, due to various factors. It's still one of my proudest achievements.

[AndyCutright]

That offset drill bit is such a simple, elegant solution. I always wondered how those worked.