Enbridge Inc. is seeking approval from the Canada Energy Regulator to implement contracting on its Mainline pipeline system.

The company's Dec. 19 application covers the associated terms, conditions and tolls of the services that would be offered in an open season after the regulator give its approval, according to a news release. The tolls and services in the application are intended to replace the pipe system's existing tolling settlement set to expire on June 30, 2021.

Enbridge's plan to shift Canada's biggest oil-transportation system to long-term contracts was previously halted by the Canada Energy Regulator, which ordered the company to first submit a plan for prior approval amid concerns that refiners and traders in the U.S. could monopolize the system and drive down Canadian crude prices.

The plan has the support of shippers representing about 70% of the Mainline system's current throughput, according to Guy Jarvis, Enbridge's executive vice president for liquids pipelines. "The most important part of this offering will be to secure long-term demand for Canadian crude oil while ensuring that all interested shippers can participate in a fair and transparent open season process," Jarvis said in the release.