CSA Ocean Sciences Inc. (CSA) has been awarded a contract from the Bureau of Ocean Energy Management (BOEM) for conducting measurements and modeling of the underwater pressure waves produced during explosive well decommissioning in the Gulf of Mexico.
The Bureau of Safety and Environmental Enforcement (BSEE) Idle Iron policy keeps inactive facilities and structures from littering the Gulf of Mexico by requiring companies to dismantle and responsibly dispose of infrastructure after they plug non-producing wells. According to BSEE’s June 2013 data, there are 356 platforms that fit the criteria for Idle Iron removal.
Many of these platforms will be removed using explosives. Although non-explosive severance methodologies (i.e., sand cutters, diver severance, abrasive water jet cutters, etc.) are also used, explosive severance charges can offer a more flexible, efficient, and safer cutting option. However, marine mammals and sea turtles may be harmed by the resulting blast pressures and potentially affected by noise levels produced during severance. BOEM, BSEE and offshore operators must comply with the Endangered Species Act and the Marine Mammal Protection Act, which requires that estimates of species impacts, or takes, must be established for explosive removal of these structures and corresponding mitigation programs implemented appropriately.
Calculation of take estimates for explosive severance is done by utilizing an underwater modeling approach that assists in predicting the shockwave, acoustic impulse, and energy flux for underwater detonations. CSA, with its project partners, Marine Acoustics, Inc. and Explosive Services International, will collect additional acoustic data under various settings during explosive severance operations. With more accurate measurements, operators should be able to increase the efficiency of their operations while providing protection to marine mammals and sea turtles.
In situ measurements from this project will enable the fine-tuning of modeling efforts, resulting in a better estimation of acoustic propagation and exposure during decommissioning activities as well as the ability to focus mitigation measures within the areas experiencing the greatest amount of potential marine species impact.
