Directional drilling provides a safe system of installing pipes, ducts and cables where conventional open cut methods are not permitted, practical, environmentally or economically viable. Sometimes called Horizontal Directional Drilling [HDD]
Typical Applications
- Steel or polyethylene pipes from 25mmØ up to 1,200mmØ in distances from 25 metres up to 1,500 metres have been successfully drilled under areas such as rivers, estuaries, roads, railways, airports, contaminatedlandfill sites and Sites of Special Scientific Interest (SSSI).
- Crossings can be for: water, oil, gas, electricity, sewerage, chemicals, communication ducts and outfalls.
Environmentally friendly with minimal disturbance The traditional method of constructing
can lead to major obstructions and objections amongst various authorities and in different areas. Horizontal directional drilling avoids breaking open or causing damage to these areas and it minimises the impact to the surroundings of the works. Advantages :
- a pipeline, in which a trench is excavated,
- Short, medium or long lengths of pipe can be installed without intermediate pits
- Pipes can be installed either straight or curved to steer clear of obstacles
- By boring underground the working area is confined to points of entry and exit only
- No disruption to road, river or rail traffic and no scarring of the landscape
- Equipment works from surface with no need for deep excavations
- HDD is quick and in many cases has lower overall costs
- HDD is unaffected by surface obstacles
- Can be used to install pipes in changeable ground conditions
- Sea outfalls can be drilled with minimal marine works
HDD in Steps
• A pilot hole is drilled according to the profile design. Directional control is achieved by using the survey steering tool system. The survey probe installed in the drilling assembly measures the survey data required for steering the drilling tool along the design profile
• The hole is then enlarged and conditioned in stages using a sequence of reamers/ flycutters/hole openers to the required diameter for receiving the product pipe
• The product pipe is then pulled into the hole by the rig
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