Herrenknecht HK 250T
Maxi rig, 250 ton pullbackOur heavyweight for long, large-diameter and sea channel crossings.
CAPABILITY 02 / 06 · Sea channel crossings
BENEATH THE WATERLINE.
Long, large-diameter HDD crossings under marine channels, creeks, lagoons and intake corridors, engineered for buoyancy, pressure and the strata beneath the seabed.
THE SCOPE
Sea channel crossings
Crossing water is where HDD earns its reputation. There is no cofferdam, no dredging and no disturbance to navigation or the marine environment: the bore passes well below the channel bed and the pipeline surfaces on dry land on the far side. Crossroad has delivered marine-adjacent crossings at Al Hudayriat, Taweelah and across Abu Dhabi's island waterways for water, power and process pipelines.
These are maxi rig jobs. The Herrenknecht HK 250T provides the pullback for long strings and large diameters, the ParaTrack 2 gyro module steers the pilot bore where walkover locating cannot reach across open water, and the drilling fluid programme is engineered for the caprock, marine sands and clays typical of the Gulf coast. Buoyancy control, ballasting and the pull-section layout are planned with the pipeline contractor so the string goes in once and goes in clean.
WHAT WE DELIVER
IN SCOPE ON EVERY JOB
- 01Crossings beneath sea channels, creeks, lagoons, marinas and intake and outfall corridors
- 02Steel and HDPE carrier pipe up to 1200 mm, single and bundled strings
- 03Gyro-steered pilot bores where surface tracking is impossible
- 04Geotechnical review and bore design for marine sands, clays and caprock
- 05Buoyancy and ballast planning, hydrotest and pullback load monitoring
- 06Environmental and marine authority method statements
HOW IT RUNS
SEQUENCE ON SITE
01
Geotechnical and design
Boreholes along the alignment, a strata model, and a bore profile with depth below the channel bed set for hydrofracture safety.
02
Gyro pilot bore
The HK 250T drives a gyro-steered pilot beneath the channel; position is confirmed by ParaTrack with no surface access needed.
03
Staged reaming
Multiple reaming passes with fluid returns managed on both banks and recycled through the mixing plant.
04
Ballasted pullback
The tested string is ballasted to neutral buoyancy and pulled back under continuous load monitoring.
See the full four-stage bore animated on the home page, or size your own crossing with the HDD tools.
IRON ON THE JOB
EQUIPMENT WE BRING
ParaTrack 2 Gyro Module
Prime Horizontal guidanceGyro steering for survey-grade accuracy where surface access is impossible.
Mixing & Recycling Tanks
Drilling fluid systemsEngineered mud programs matched to UAE soil strata.
ON RECORD
CROSSINGS LIKE YOURS
STRAIGHT ANSWERS
QUESTIONS WE GET ASKED
Engineers answer every enquiry. If your question is not here, send it over.
01How deep below the seabed does the bore run?
Deep enough to keep annular pressure well below the formation fracture limit at every point of the profile, which in Gulf conditions usually means 10 to 25 m below the channel bed. Depth is fixed by the geotechnical model, not by a rule of thumb.
02Can you steer accurately across open water?
Yes. The ParaTrack 2 gyro module measures the drill head azimuth and inclination without any surface reference, so the pilot bore can be steered on long crossings where no walkover locator could follow. Exit accuracy is within a metre on crossings of several hundred metres.
03What about the marine environment?
The seabed is never touched. There is no dredging, no turbidity and no interruption to vessel movement. Drilling fluid returns are contained at the entry and exit pits and recycled.