Horizontal Directional Drilling / Boring (HDD): How the Drill Bit is Steered

directional drilling makes construction

projects like this one possible

let's rewind and take a look at the

directional part of the drilling the

impressive accuracy of horizontal

directional drilling is achieved through

careful planning well trained navigators

guidance software proper setup and

advanced steering tools a skilled

driller can direct the course of the

drill bit along a pre-planned path over

great distances different formations

however require different techniques in

alluvial or soft formations a jetting

assembly uses high-pressure fluid to

remove formation while drilling the

steering tool transmits data to the

Navigator the driller can now orient the

bend and the hydraulic pressure toward

the desired direction the nozzle aligned

with the bent sub focuses intense

hydraulic pressure to a chosen direction

it's like holding your thumb across a

garden hose to increase the spray

pushing forward the bit follows the path

of least resistance guided by the

deflection of the bin once this

directional adjustment is complete the

driller can go back to rotating the

drill string harder formations require a

different approach a drill motor

replaces the jetting assembly now the

hydraulic pressure is used to drive a

turbine which rotates the bit without

having to rotate the drill string this

allows the driller to orient the bend

and drill in the desired direction the

string is pushed forward or slid guided

by the deflection of the bend

once this directional adjustment is

complete the drill string can again be

rotated at regular intervals steering

data is gathered and adjustments made