By the time the reamed hole is ready, the entire product pipeline has to be waiting on the surface — welded, inspected, coated, tested, and laid out so it can be pulled through the bore in one clean operation. That staging is the pull-section fabrication, and it depends on having enough workspace of the right shape. This article covers how the pull section is built and supported, and why the workspace on the exit side is a make-or-break planning item.
Build It Before You Pull It
The pull section is a prefabricated pipeline: the joints are welded into a continuous string, the welds are inspected (typically radiographically), the corrosion coating is applied and field joints coated, and the whole string is hydrotested before installation. All of this happens on the surface, before pullback, so that the only thing left to do during the pull is move the pipe into the hole. Doing the quality work up front is what lets pullback proceed continuously.
Why Continuous Pullback Matters
The strong preference is to fabricate the pull section in one continuous length so it can be installed without stopping. If workspace forces the pipe to be built in two or more segments welded together during the pull, the installation slows down at each mid-pull weld — and every pause is dangerous, because a stationary pipe in a relaxing borehole is far more likely to become stuck. Continuous pullback keeps the pipe moving and the loads predictable, which is exactly what the pullback force model assumes.
The Workspace Requirement
The ideal workspace is a straight, clear corridor in line with the drilled segment, extending back from the exit point for the length of the pull section plus about 200 feet of extra room for equipment and handling. That extra length lets the string be assembled, tested, and fed into the hole in one piece. When a site cannot provide it — a constrained far bank, a road, a property line — the alternatives are all worse: segmented fabrication, a curved layout that adds bending, or a temporary trench to string the pipe. Workspace availability is one of the first things to check when siting the entry and exit points, because it can override an otherwise ideal geometry.
Supporting the Pipe During the Pull
As the pull section is drawn into the hole it must be supported so that its own weight and the pull geometry do not overstress or damage it. Several tools do this job:
- Roller stands or pipe-handling equipment carry the string off the ground, minimizing surface drag and coating damage as it moves.
- A breakover ramp (or elevated roller array) lifts and gently bends the pipe over to align with the descending exit angle without kinking it — the reason exit angles are kept shallow.
- A swivel connects the pull section to the reaming assembly ahead of it, so the rotation of the drill string and reamer is not transmitted as torsion into the product pipe.
- A flotation ditch is sometimes used in place of rollers, floating the pipe in water to control its effective weight and support during the pull.
Multiple Lines in One Hole
More than one pipeline can be installed in a single bore by joining them to a common pulling head. The lines need not be banded together, but they should follow the head freely into the hole; where cathodic separation is required, rubber spacers or a thick resilient coating keep them apart. Because the bundle rolls as it is pulled, workspace outside the drilled segment must allow the lines to be repositioned for tie-in afterward.