Horizontal Directional Drilling

In order to overcome longer obstacles than in case horizontal drilling, the use of horizontal directional drilling
is needed.

In this case the pipe diameters are usually no larger than 56"(1422 mm), and the length of the drill pass can be up to 5 kilometers.


The horizontal directional drilling procedure consists of the following:


1. A narrow tunnel with the required trajectory is created
by a drilling head that is attached to a flexible rod. The flexible rod allows for control of the drilling head and its direction.

Drill auger position is controlled constantly and operator any moment can correct deviation.


pilot borehole drilling


2. A special reamer is fitted on
the pipe that is ready to be pulled through the tunnel. The end of the reamer is attached to the flexible rod.

With the help of pressurized water, the reamer that is attached to the pipe widens the tunnel until the necessary diameter is achieved.


borehole reaming


3. The flexible rod begins to travel in the opposite direction while pulling the pipe.

This way the pipe is pulled through the entire tunnel that was created earlier.


pipeline pulling


Pulling of pipe through the tunnel can create
a lot of pressure on the coating.

This problem is solved by applying Ceramguard to the pipe.

When three-layer coating is used, the joints
of the pipe are protected with "TBK" heat shrink sleeves (for fuller description, see Pipeline Corrosion Protection).


pipe with reamer
is pulled towards the tunnel

after travelling
through the tunnel,
the pipe emerges at the surface