By Jessica Lin and Janet Rodriguez

Oil Rig  Removal
Source: Proserv Offshore Inc. 

Keep Drilling, or Remove the Rigs? 

Today, politicians, economists, and environmentalists all hold a wide range of opinions on oil as a nonrenewable resource. Some insist that we continue drilling for oil while others claim that the transition to a renewable energy source is necessary. While oil reserves proliferate the Middle East, the California coast is has been a highly sought area for oil drilling. As a part of the gradual transition to other energy sources, there is a push to completely remove oil rigs. In this study, we focus on understanding the effects of decommissioning oil rigs on the California coast, specifically the Southern California  Bight, and why each decommission should be treated on a case-by-case basis. 

Area of Study: Southern California Bight
Source: Schroeder and Love, 2004

History of Oil Rig Decommissioning

The very first offshore drilling activity took place in the Gulf of Mexico, also making it the first region where decommissioning oil rigs has been taken into serious consideration. The Gulf of Mexico currently has over 5000 oil rig platforms. The coasts of Louisiana and Texas have been subject to the most decommissioning (oil rigs were often removed entirely). Throughout most of the decommissioning, there was little consideration regarding ecological and environmental impacts.

The Southern California Bight and California coastal areas have not been subject to decommissioning in the past. However, as of 2003, there has been more serious federal consideration about removing oil rigs in the area. The platforms on the California coast have been dug much deeper in to the ocean floor and also affect local transmission line and pipeline operations. 

How the Oil Rig Works

Oil currently supplies about 36% of the U.S. energy demand.  Below is a prototypical oil and gas production platform in the Southern California Bight. The crew resides on the insulated topside facilities and deck. Conductive vertical pipes transport the oil and gas and are connected to the depths at which oil is extracted. A combination of electrical generators, a turntable, hoisting system, and high-pressure valves control the amount of oil drawn in from the circulation system to avoid blowouts and filters oil from the mud. 

Oil Rig/Gas Production Platform
Source: Schroeder and Love, 2004

Impacts on Marine Ecosystems 

Decommissioning of oil facilities are impacting the marine environments the most. Worldwide there are an estimated 6000 oil and gas platforms. Once the oil platforms become obsolete, the removal process or decommissioning is costly, and harmful to the marine environment. The Gulf of Mexico has dealt with problem of removing the obsolete oil platforms including the states of Texas, Louisiana, and Florida. With 6000 oil platforms around the world, decommissioning will become a prominent issue in these countries with these types of platforms such as the United Kingdom. As the marine diversity is being affected, the global fishing industry may plummet.

Number of fish per depth near oil rigs
Source: Appen Oil and Gas Decommissioning report

Oil rigs are built differently and each serve a different purpose.

Source: Appen Oil and Gas Decommissioning Report

Solutions and Alternatives to Complete Oil Rig Removal

As we slowly transition into sustainable energy such as solar or wind, more platforms will become obsolete. A solution to the decommissioning of platforms is to leave the oil platforms in place. If the platform is completely removed, many of the organisms which have associated to and adapted to the oil platforms’ presences may die out. This will dramatically reduce the diversity and amount of species. The underwater explosions used to separate the platform from the sea floor create strong shock waves which will cause immediate lethal impacts for marine life on or near the platform. Destruction of marine life will affect the global economy and fishing industry, as a significant number of individuals rely on fish and other seafood as a primary source of protein in their diets. 

An alternative to the total removal is partial removal. Partial removal eliminates some of the shallow water habitat from the marine environment; this still results in a decrease of the abundance of species. However, partial removal does not require the use of explosives which avoids the mortality of fishes and invertebrates. Toppling is another alternative and in the long run changes the type of diversity of fish in that area. The last alternative is to leave the platform in place. Leaving the platform in place, along with partial and toppling create artificial reefs, serves as an overall habitat enhancement. This alternative has zero to minor mortality impacts to the marine environment. The estimated life span of a platform before it beings to rust underwater is 100 to 300 years. It is realistic for the platforms to be left in place. Furthermore, each oil rig is very different in its construction and infrastructure. It is important for each possible decommissioned rig to be evaluated on an individual basis.

Source: Schroeder and Love, 2004

How has policy addressed oil rig decommissioning? 

When looking at this issue from an ecological perspective, apart from the oil rigs being an eyesore, oil rig removal is costly and has detrimental impacts to the its surrounding marine population.  In the Southern California Bight the California Artificial Reef Plan has been created which sets guidelines based on the rigs-to-reefs program, which keeps oil rig platforms as artificial reefs. This policy began in the Gulf of Mexico. The guidelines are as follows:

(1) Benefit living marine resources, habitat, and user groups

(2) May not be used to dispose of contaminated materials

(3) Endeavor to leave the subsurface structure of the platform in place and where possible subsurface structure that must be removed could be relocated to the base of the rig or other appropriate sites.

General Conclusions

Oil rig decommissioning is a controversial issue. On a more basic level, there are already economic debates and political dissent regarding the continued use of oil or switching to renewable energy sources. Due to the unique nature of each oil platform and the diverse ecological environments along these oil rigs, oil rig decommissioning requires a case-by-case analysis. The decommissioning process is not likely to be resolved anytime soon. Policies involving drilling and renewable energies are controversial and seldom reach a compromise. Furthermore, the scientific research behind oil rig decommissioning is still young and is not widely accepted in the scientific community.

The decommissioning process teaches us the complexity of not only oil-related technologies, but also other environmental concerns and how much of the environment is interconnected. In particular, as there is a gradual transition to cleaner energy solutions, there must be a stronger consideration about how new developing technologies will affect the environment from multiple perspectives.

References
(1) Schroeder, Donna and Milton S Love. "Ecological and Political Issues Surrounding Decommissioning of Offshore Oil Facilities in the Southern California Bight." Ecological and Political Issues Surrounding Decommissioning of Offshore Oil Facilities in the Southern California Bight. Web. 2 Mar. 2015. Ocean and Coastal Management Journal, 2004.

(2) Bernstein, Brock B."Evaluating Alternatives for Decommissioning California’s Offshore Oil and Gas Platforms." Web. 1 Mar. 2015.  <http://calost.org/pdf/science-initiatives/oil-and-gas/OilandGas_DecommissioningFullReport%28WithAppen%29.pdf>