How do you steer a directional drill bit?
Directional drilling, also known as horizontal boring or directional boring, begins with the directional drill bit entering the ground at a certain predetermined angle. The pictures below demonstrate a directional boring bit at several different clock faces.
For simplicity, let’s start this directional bore off with the clock face at 6 o’clock. The
directional bore operator penetrates the ground with the bit at 6 o’clock then uses a combination of pushing and rotating the tooling until its descent is complete.
Typically, a directional bore path requires approximately five feet of horizontal distance for every 1 foot of vertical depth change; this is referred to as the set back. The set back required for a directional bore at a 5’ depth below ground surface would be 25’.
The operator begins by rotating the drill bit into the ground for a certain distance at which point the angle the bit entered the ground must be change or the target depth of 5’ will be missed. The directional boring operator will rotate the directional boring bit to the correct tool face or clock position and push the directional boring bit a certain distance.
This procedure is repeated to change the pitch along the course of the bore until the required 5’depth is reached. The drill bit is then rotated until a new steering command is given along the directional bore path. Most directional bores have an exit point so the
end of the directional bore is approached the drill bit will then be rotated to the 12 o’clock position to begin the ascent to ground level.
During the directional boring there may be a planned or unexpected obstacle that may have to be circumvented. In this case the directional boring operator again can steer the drill bit by rotating the face. If the directional drill bit needs to go left then the drill bit face is rotated to the 9 o’clock or if the drill bit needs to go right then the face is rotated to the 3 o’clock position.
It is very common in directional boring that the boring operator changes the position of the directional drilling bit to keep the bore path on track.
Ground conditions during directional boring will dictate the amount of steering necessary to complete the directional bore. If the subsurface conditions are cobble, it will require a very experienced crew to keep the bore path on track. The experienced directional boring crew will also be able to circumvent larger boulders by either going left, right or deeper.
Directional Technologies, Inc. has been directional boring for over 20 years and is the nation’s expert horizontal remediation well drilling contractor. Please contact us at email@example.com or 203-294-9200 to learn more about our capabilities.