The Company is pleased to advise that the HDD team on the IRPC Natural Gas Pipeline Project in Rayong, Thailand, successfully completed a 1,877 m long horizontal directional drill using the intersect technique on Wednesday, 2 June.

The drill was completed using McConnell Dowell's American Auger DD625 rig in conjunction with two other HDD rigs supplied by our subcontractor, Strega.

The team used the 280 tonne capacity DD625 rig to drill a 121/4" dia. pilot hole at depths of approximately 30 metres over a length of 1,817 metres. Due to the softness of the soil formation at the far end, steering past this point became difficult. This rig was equipped with the Paratrack 2 steering system which includes a magnetic field source located 8 m behind the cutting head and mud motor.

A second smaller rig (Vermeer D80) was set up at the planned exit point and was used to steer a second (3.5" dia.) drill string over 60 m to intersect the cutting head of the McConnell Dowell rig. Using a second Paratrack 2 system, the steering engineers were able to guide the 3.5" diameter drill string downhole until the two cutting heads touched.

A third HDD rig (American Augers DD140) was then used to install a larger diameter drill string over the top of the 3.5" dia. drill string prior to installing a 14" diameter casing pipe to the intersect point. The casing pipe provided a stable path for completion of the original drill.

The crew is now setting up to drill a parallel hole of a similar length for the installation of the 24" diameter gas pipeline.

The intersect technique is now increasingly being used around the world to extend the length of HDDs, as previous limits have now been bettered, and using this technique HDD exceeding 3,000 m have been completed.