Introduction of Horizontal Directional Drilling Equipment

• Nov 18, 2021
• The equipment used in Directional Boring/HDD depends on the length of the (proposed) crossing, the pipe properties (of the to-be-installed pipeline), and the (anticipated) subsurface conditions....

The equipment used in Directional Boring/HDD depends on the length of the (proposed) crossing, the pipe properties (of the to-be-installed pipeline), and the (anticipated) subsurface conditions.

For longer more challenging crossings, tractor trailer mounted drills capable of 1,320,000 lbs (thrust/pullback force) and 150,000 ft-lbs (rotary force) may be used [600 tonnes- 204,000 N-M ]. These units are used in conjunction with a drilling fluid reclaimer, high volume pump or pumps, an excavator (or comparable equipment for managing drill pipe), along with an assortment of other ancillary equipment (e.g. water tanks, spoil containers, etc.) to facilitate typical operations.

 

 
 

For smaller bores, proportionally smaller and more portable equipment is available. These units may be capable of anywhere from 5,000 lbs to 100,000 lbs of thrust/push force and may be used for spanning between a house basement to a nearby shared water pipe. Fluid exhaustion associated with smaller bores is proportionally less as well. In many instances, smaller bores do not require the use of drilling fluid, only water, and in even less significant bores no fluids at all. 
 

Tooling, as in the mechanical apparatus that are installed to the drill string to conduct operations, are available in a wide number of different shapes and sizes. Directional Boring/HDD tooling includes the suite of drill bits or drill heads used during pilot hole operations, reamers and hole-openers used for hole enlargement, and swab tools which are used for hole conditioning and pullback. Tooling intended to navigate rock, or tougher formations, may use tungsten carbide alloys or Polycrystalline Diamond (PCD). In contrast, tooling intended to navigate soft soils may be limited to high carbon steel (milled to a desired shape and size).

The methodology of advancement also varies somewhat between soil and rock crossings. Advancement of tooling within loose uncemented soils is largely accomplished by hydraulic excavation. That is, the soil is being cut and or removed under the influence of high pressure fluid. Within rock formations, hydraulic excavation is still taking place to some degree (evacuating spoil) but the lion's share of cutting and breaking up material is due to mechanical work being done by the tool itself.