Decommissioning Activities

Decommissioning activities are an important part of OCS activities. Nearly 4,000 active platforms exist in the OCS, one quarter of which are over 25 years old and in sight of the end for their designed service life. Industry is removing approximately 100 platforms each year with removals nearly equaling the number of new installations. In most cases in the OCS, upon removal of a platform, the topsides that contain the operational components are taken to shore for recycling or re-use. The substructure is generally severed below the mudline, removed, cleaned, and brought to shore to sell as scrap for recycling or refurbished to be installed at another location.

Another option, used for about 10 percent of the removed structures, is to tow and install the structure to an approved artificial reef site using the criteria in the National Artificial Reef Plan as permitted by U.S. Federal agencies. The U.S. State government agency responsible for managing marine fisheries resources manages the program. The MMS supports and encourages the reuse of obsolete offshore petroleum structures as artificial reefs in US waters.

However, the structure must not pose an unreasonable impediment to future mineral development. Also, the reuse plan must comply with the artificial reef permitting requirements of the Corps of Engineers and the criteria in the National Artificial Reef Plan. The state agency responsible for managing marine fisheries resources must accept liability for the structure before MMS will release the Federal lessee from obligations in the lease instrument. As appropriate, MMS may facilitate cooperation between Federal lessees and other state and Federal agencies concerning the reuse of the structure. The MMS will share information with others concerning the environmental, social and economic consequence of reusing the structure as an artificial reef.

The MMS, in it's update of the decommissioning regulations, incorporated comments from the proposed regulation published in the Federal Register on July 7, 2000, (65 FR 41892), and comments supplied at International Decommissioning Workshops including the following:

Challenges lie ahead for the platform removals from the OCS, particularly for those large platforms (> 10,000 tons) located in deeper waters. The water depth, lack of local infrastructure, marine environment, limited availability of equipment, and regulatory constraints are all challenges to be worked through. The MMS is evaluating these challenges through its research program.

Future Decommissioning Research:

Methods to improve operational safety of personnel through policy, procedures and equipment improvements. The MMS TAR program remains attentive to materials and systems technology that

reduces or eliminates vessel assisted lifting and transport (i.e., buoyancy assisted towing support) and
improves or replaces bulk-charge explosives (i.e., engineered (lower charge) explosives or hydraulic assisted cutters).

Recognizing the challenge facing removal of larger facilities now being constructed, analysis of platform and pipeline removal operations is expected to address the

lack of large scale vessels, equipment, and onshore handling facilities and
structures disposal alternatives such as the Artificial Reef Program that has been shown to enhance fish populations and reduce shoreline deterioration.

For more information, please email Michael Else.

Decommissioning Projects

025 Overpressures Developed by Shaped Explosive Charges Used to Remove Wellheads

044 Environmental Effects of Wellhead Removal by Explosives

112 Project Cancelled

118 Blast Effects Upon the Environment from the Removal of Platform Legs by Explosives

232 Investigation of New Techniques for Abandonment of Offshore Structures

234 Lease Abandonment: Technology, Environmental Effects and Regulation (Lease Abandonment Workshop)

267 Development, Testing and Evaluation of an Explosive Shock Wave Focusing Tool with Minimum Explosive Weight

270 Decommissioning of Oil and Gas Facilities Offshore California Workshop

329 Risk Assessment of Temporarily Abandoned or Shut-in Wells

337 Project Cancelled

352 Assessment of Current Pipeline Flushing and Decommissioning Requirements - Research and Field Testing

355 Using Satellite Radar Imagery to Detect Leaking Abandoned Wells on the U.S. OCS

372 State of the Art of Removing Large Platforms Located in Deep Water

429 Oil Platform Removal Using Engineered Charges: In Situ Comparison of Engineered and Bulk Explosive Charges

459 Comparative Risk Assessment of the Decommissioning Options for Large Platforms in the POCSR

480 An Assessment of Safety, Risks and Costs Associated with Subsea Pipeline Removals

537 A Study of Underwater Gaseous Explosions

570 Measurement of the Effect of Depth Below Mudline of Charge Placement During EROs

600 A Review and Update of Supplemental Bonding Requirements in the Gulf of Mexico