TransCanada Severn River Gravenhurst pipe replacement
Scheduled to be a Soft Rock (maximum 90MPa unconfined compressive strength) Direct Pipe Installation, IPC was awarded to set up and install a 400m, 36” product pipe in the fall of 2017.
Due to the uncertainty of the rock impact on the product pipe coating, the client and IPC decided to install a 42” sacrificial pipe to allow a safe 36” product pipe pull in from the drilling exit side. The execution strategy planned for the connection of the 42” sacrificial pipe and the 36” product pipe on the exit side, followed by a pull in of the product pipe while extracting the sacrificial pipe.
CHALLENGE
IPC faced several challenges – scheduled and unscheduled:
Scheduled:
Transition from hard rock into soft and high permeable sand (zero blow count). Drilling operation through the transition while ensuring accuracy and zero environmental impact. Pull in scenario had never been executed this way in North America before.
Unscheduled:
After set-up and commencement of drilling, the Geotech appeared to be up to 3 times harder than predicted. Maximum unconfined Rock Strength of 227MPa in Canadian Shield. Abrasivity of 4.6 on the Cerchar Index. • Last minute design changes extended the rock drilling section from 80m to over 160m.
ACTION
IPC adjusted the tooling on the Cutter Head structure accordingly.
Frequent maintenance runs were performed to maintain the equipment integrity.
Frequent tool changes allowed to IPC finalize product pipe installation in an extended time schedule.
RESULT
The client and IPC shared the challenges on this unique Direct Pipe Crossing. All teams and people involved deserve the highest respect for the finalization of this project in a professional and collaborative manner. Ultimately, IPC managed another successful pipe installation to the client’s satisfaction.
