Case Studies
Custom Rigs
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Hillcorp Innovation
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WFC Hitchwheeler
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Material Handling
Doyon Pipe Handling
Walking Systems
Pony-Sub Walking Box Rig
Autowalk Series
Equipment Rebuilding
Competitor's Walker Refurb
Jack Cylinder Rebuild
Suspension Cylinder Rebuild
Competitor's Stomper Feet Upgrade
Entro Walker Rebuild
trailer rebuild
Autowalk Series for Ideal Rigs

The Need for Speed

A customer needed a better way to move NOV Ideal rigs on the pad in the lower 48. They had some tough requirements: fast hole-to-hole times, fast rig-up/rig-down times, high accuracy, and minimal pieces to handle. Their drill program would involve setting up a pad in remote areas, quickly drilling multiple holes on the pad, and moving on to the next pad as soon as possible. They needed a system that had as few separate pieces as possible to simplify handling, and they needed to be able to assemble the rig with as little crane assistance as possible. To simplify moves from hole to hole, they needed to move their mud boat with the rig as a single piece, without lifting it with a crane. Lastly, the client was looking for additional height under the rotary table of the rig.


The customer's need for fast hole-to-hole moves would require something more sophisticated than a typical manual walking system. While a manual Entro walking system is orders of magnitude faster than many other systems for moving a rig on a pad, the customer needed to improve the efficiency of their rig walking operations. The slowest operation on a manual Entro walking system is adjusting steering because each foot is lifted off of the ground and turned by manually rotating a gear with a ratchet.

Figure 1. A simple ratchet allows quick steering adjustments for manual walking systems.

Providing a King-pin Walker with power steering would substantially improve the speed of the walking system, but even further improvements in speed could be realized by automating the entire walking process - lift, travel, and steering - so that all inefficiencies could be eliminated from the walking cycle. The customer also required a walking system that disassembled down into as few separate pieces as possible to simplify their logistics, and also didn't want any major structural modifications to their current substructure. These two requirements both pointed towards a Pony-Sub solution, where each box on the rig substructure is placed on top of a full-length module that carries two complete walking feet.

Figure 2. Pony sub systems are often tall, but can be made quite low-profile if needed.

By placing two walking foot assemblies in one box, the number of crane picks required to rig-up is cut in half. And, by putting the entire walking system and supporting structure in a single module, no significant structural modification to the existing rig was required.

The customer needed to walk their mud boat with the rig, without using a crane. By taking advantage of the rig walking system, a simple jacking system could be used to lift the mud boat straight up to allow the rig to walk underneath it, simplifying the rig-up procedure.

The Solution

Figure 3. The Pony Sub used with the AutoWalk system has a low profile, minimizing the modifications required for the pipe-handling and festoon systems.


Figure 4. The controller developed for the AutoWalk system allows the operator to steer in the desired direction and walk the rig as far as desired without further inputs.

To meet the customer's requirement for quick moves, Entro Industries developed patented controls technologies to allow faster rig moves. The AutoWalk and AutoLift systems were developed to allow an operator to walk a rig like a remote-control car; an operator would pick a direction of travel and the system would automate the entire walking cycle. The result was a walking cycle that could complete rig moves in a fraction of the time of manual systems.


Figure 5. The pony sub is pinned to the customer's substructure.

Entro provided the walking system in a low-profile Pony Sub package that integrated wire harnesses, hydraulics, and machinery into a single load. Each pony sub was a single truck load and could be picked up with a crane. The customer's substructure sits on top of the Pony Sub boxes and pins in place with a kit provided by Entro.

Additional Equipment

Figure 6. The mud boat lift raises the mud boat into the air.

To raise the customer's mud boat onto their substructure without a crane, a special jacking skid was provided that would lift the mud boat above the rig and allow the rig to walk underneath it.