Southern Conduit Completed
Tuesday, March 15, 2011
On Friday, March 11, the drilling rig broke through the seafloor, ahead of schedule, at the end of the 5,000-foot southern conduit. Next step, on March 12, was to bring the drill rig out of the hole and back to shore and to begin pushing in the 5-inch steel pipe, which will serve to protect the electro-optical cable.
On Monday, March 14, the southern conduit was successfully completed after the drilling crew worked through the weekend. The conduit end on the seabed was capped to prevent inflow of water and sediment until the cable is installed in summer 2011.
As of Tuesday, March 15, the drilling rig has been repositioned to begin work on the northern conduit that will be used to pull in the cable to the Axial Seamount study site.
Video description: Video shows the drilling team pulling the 12-3/4 inch casing from the 700-foot pilot hole at the conduit's shore end near the shore station in Pacific City, OR. The casing (steel conductor pipe) was meant to prevent the first 700 feet of the hole from collapsing, providing a guaranteed hole through the first radius (bent at depth) and to add stability in the event that the last 1000 feet of drilling becomes difficult to push. It was also designed to prevent the loss of circulation, reduce torque and prevent key seating in the bore hole. The hole was filled with drilling mud throughout the above processes. This hydraulic pressure helps prevent the hole from collapsing during the removal and prior to the insertion of the drill pipe.