Shell Canada's replacement riser has arrived at the Port of Halifax, however the company's offshore exploration remains on hold until it uncovers how it lost the first one.

A riser is a specialized vertical pipe that connects a surface ship to a wellhead on the sea floor. On March 5, rough weather caused a drill ship hired by Shell Canada to drop a roughly 2,000-metre riser to the bottom of the ocean.

At the time of the incident, crews had disconnected the pipe from the bottom and had taken steps to prevent any oil or drilling fluid from escaping.

Shell Canada's riser is still laying at the bottom, while at least eight long Styrofoam sheaths have broken off the pipe and floated away.

The company was nearly finished drilling the first of two planned exploratory wells, searching for oil and natural gas about 225 kilometres off Nova Scotia's coast. However, drilling has been suspended ever since the March 5 incident.

"Until such time as the board is satisfied that operations can proceed safely, drilling will remain suspended," said Kathleen Funke, spokesperson for the Canada-Nova Scotia Offshore Petroleum Board.

Shell offshore riser pipe worker

Pipes were unloaded from a cargo ship, transferred to a flat bed truck and onto the Port of Halifax wharf. (Brett Ruskin/CBC)

Nonetheless, Shell is preparing for when operations can resume.

Dozens of segments of pipe were offloaded Monday morning at a north-end Halifax pier. The pipes will eventually be shipped out to the drill site, fitted together vertically, and lowered down to replace the original riser.

Shell Canada officials say they are still investigating the cause of the March 5 incident.