The delay is due to Shell's takeover of the project after its $53 billion acquisition of BG Group in 2016 prompted it to re-evaluate and strike new agreements.
Proposal would shift to long-term, fixed volume contracts from allocation on a monthly basis.
The agreements end a dispute over the $2.5 billion South Texas-Tuxpan natural gas pipeline that was completed in June but has not been in operation.
PHMSA says it won’t allow the company to restart two lines until an investigation is complete.
Iraq's oil ministry said on Aug. 10 it was still in talks with Exxon Mobil Corp. over a major deal to improve the country's southern oil infrastructure.