The Oil & Gas Industry and the Environment

Platform Decommissioning

Decommissioning and disposal of offshore installations has been the subject of extensive debate. Public concern is evident, and in some cases has become a significant factor in the search for the most appropriate decommissioning solutions.

One of the main difficulties with decommissioning is finding the right balance between:

  • Technical Feasibility
  • Environmental Protection
  • Health and Safety
  • Cost
  • Public Opinion

The process of decommissioning is very strictly regulated by international, regional and national legislation. More >>

The the options available for decommissioning will depend on the location of the offshore facility and subsequent legislations. One of the most important steps in the decommissioning process is planning ahead.
 
Depending on legislation, a number of options may be available for decommissioning:
■ Reuse for oil and gas purposes
■ Complete removal
■ Partial removal
■ Deepwater disposal
■ Leave in place - abandonment
■ Reuse for other purposes e.g. artificial reef

Diagram of dismantling and abandonment options for offshore installations and component parts.

Excerpt on the Reuse of Offshore Platforms
from “Abandoning Offshore Platforms: Offshore-Platform Decommissioning Perceptions Change” by Ron Twachtman.

 
The decommissioning and proposed deepwater disposal of of Shell UK’s Brent Spar sparked controversy. More >>

Maureen is unique offshore facility that combines production, drilling facilities, oil storage and accommodation in a single platform which was designed for refloat and re-use from the very beginning of the design phase. More >>
 
 
■ UK Offshore Operators Association
■ DTI Decommissioning
■ Environmental Impacts of
   Decommissioning Oil and Gas installations
   in the North Sea
■ Decommissioning, abandonment and
   removal off obsolete offshore installations
■ Ospar Commission
■ International Maritime Organisation
 
   
 
Excerpt on the Reuse of Offshore Platforms from “Abandoning Offshore Platforms: Offshore-Platform Decommissioning Perceptions Change” by Ron Twachtman.

Reuse
Although newer techniques have furnished alternative ways to reduce decommissioning expenditures, the costs for decommissioning services and equipment are currently increasing. In addition, the cost for fabricating new structures is also increasing… one current tend for offsetting costs is to reuse a portion or all of the offshore facility. Although reuse has primarily been used in the Gulf of Mexico, many operators are considering this option in other locations, such as West Africa and Southeast Asia.

Another possibility for facility reuse is the use of old platforms for functions besides oil and gas production. Some conceptual applications investigated are the conversion of offshore structures into fish farms, prisons or military outposts. Artificial reefs made from decommissioned oil and gas structures have been popular with sports fisherman and divers in the Gulf of Mexico.

Diagram of dismantling and abandonment options for offshore installations and component parts. From: "Environmental Impact of the Offshore Oil and Gas Industry" by Stanislav Patin.