Some five months after the fencing arose in a local park for the HDD works, the local community have had at least partial amenity returned with the fences having come down. Since the HDD works were completed late last month, CoeDrilling has removed all its equipment and begun returning the site to its original condition.
With the crushed rock hard stand removed, the 300mm of removed topsoil has been replaced making the surface of the park close to level. Due to the close proximity of the land cable installation and damage to the lid of the beach manhole, final levelling and re-turfing has been delayed until after these works so that the new turf is not disturbed.
Following various tasks coordinated between the HDD team and the divers (proofing and pigging runs), the hauling line will be installed bringing the HDD installation to a close by the end of next week. Completion of the HDD project will include installation of the Beach Manhole and remediation works to return the park to better than original condition.
Our Project Manager John Bradfield (above) was given the priviledge of driving the rig to push the final tube through.
On Monday 1st December, divers confirmed that the HDD punchout is in an excellent position for the cable landing with 200-400mm of sand cover and a fairly clear path seaward with no large obstacles. The 158 lengths of drill pipe have now been extracted and removed from site and the steel tube which will be inserted to permanently stay in the hole to house the submarine cable has been delivered to site. Installation of the steel tube began on Saturday 6th December and was completed yesterday.
The above photo shows the last tube being inserted and the purging of air from the seaward end of the tube.
The HDD punchout was planned for Monday the 1st December however it was achieved early at lunchtime on Saturday 29th November just before end of work for the day. The pipe has exited the seabed in approximately 15m water depth at 1515m from the drilling entry point.
This picture is of the seaward punchout as illustrated by an extremely minor discolouration in the water. The three fisherman in the tinnie showed no recognition of what was happening between 20 – 50m away as they drifted past.
As the HDD project approaches the finishing line and we prepare for the punch out day, it’s good time to review the overall quality and environmental management aspects of the works that started early September. Brett and John conducted an onsite review with our drilling contractor, Coe Drilling. This involves reviewing the site daily logs and incident reports to ensure the requirements of the site environmental plan have been met, not been met, just met or exceeded. We also took the opportunity to commence the planning for the punch out which we hope will occur before the end of the month.
Above is a picture of a drill operator splicing a wire cable into a section of ppipe. This small gauge wire is spliced into each new section of pipe as the pipe is being loaded onto the horizontal drill rig in preparation to be drilled into the ground. This wire runs the entire length of the sectioned pipes that have been installed and is connected to the drill head in the end of the farthest section of the pipe. Information from the drill head is passed back up to a computer that displays an output to the drill operator of exactly where the drill head is. The drill operator can then adjust the drill head to make it go up, down, left or right, or basically, steer it in the desired direction.
While it may look like a simple little wire, it is actually very crucial to the HDD drilling operations as we need to know at all times where the drill head is and where it needs to go so that our pipe/ducts come up where we expect for our cable entrance in the ocean.
On Saturday the Coe Drilling and PIPE International team hosted a BBQ on the site of the Horizontal Directional Drilling. Progress has been steady with the current drill position at approximately 1,000m.
The BBQ gave the local community a chance to ask questions and for the PIPE International team to explain what we are doing and why we are doing it.
This week, the HDD in Sydney had to overcome the breaking of the locating wireline.
The wireline is used to transmit information through a cable, fitted within the drill string. The transmitter, located behind the bore head registers angle, rotation, direction and temperature data. At the surface, the signals from the transmitter are decoded and steering directions are relayed to the bore machine operator.
The wireline was withdrawn and repaired. The drill string was put back down the hole to allow drilling operations to continue.
The delay has caused only a slight setback of a few days at the HDD site.
The HDD is making solid progress having now reached a length of 656m from the Beach Manhole. The existing hole is being enlarged from 9 7/8″ to 12 1/8″ to assist the mud return with cuttings.
The reaming process should see the drill back on the bottom of hole tomorrow.
How does the drill operator follow the route and make sure that the drill is in the right line and right depth when drilling the HDD?
The horizontal directional drill utilises the wire line system. The wire line system is made up of 5 components:
- The probe
- The interface
- The driller’s console
- A computer
- And a printer.
The probe has 2 sections, 1 for the electronics and another for the sensor. The electronics section contains the circuitry that powers the sensor section and translates the data. The sensor section contains 3 accelerometers and 3 magnetometers. The accelerometers give the inclination, (up and down angle). The magnetometers give the azimuth movement (left and right angle).
This information is transmitted to the surface through the same wireline that provides the power to the probe and also receives and translates the data from probe. The data is sent to the computer and the driller’s console. The driller’s console has a 360 degree dial in 5 degree increments that monitors the orientation of the drilling head. It also provides the inclination and azimuth at any given point.