30 C.F.R. § 250.1751 How do I decommission a pipeline in place?
Title 30 - Mineral Resources
Link to an amendment published at 71 FR 40913, July 19, 2006. You must do the following to decommission a pipeline in place: (a) Submit a pipeline decommissioning application in triplicate to the Regional Supervisor for approval that includes the following information: (1) Reason for the operation; (2) Proposed decommissioning procedures; (3) Length (feet) of segment to be decommissioned; and (4) Length (feet) of segment remaining. (b) Pig the pipeline, unless the Regional Supervisor determines that pigging is not practical; (c) Flush the pipeline; (d) Fill the pipeline with seawater; (e) Cut and plug each end of the pipeline; (f) Bury each end of the pipeline at least 3 feet below the seafloor or cover each end with protective concrete mats, if required by the Regional Supervisor; and (g) Remove all pipeline valves and other fittings that could unduly interfere with other uses of the OCS.
Title 30: Mineral Resources
PART 250—OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF
Subpart Q—Decommissioning Activities
Pipeline Decommissioning
§ 250.1751 How do I decommission a pipeline in place?

