An Assessment of Techniques for Removing Offshore Structures (1996) / Chapter Skim
Currently Skimming:
Summary Assessment of Explosive and Nonexplosive Technologies
Summary Assessment of Explosive and Nonexplosive Technologies
Pages 50-54
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 50... ...
Cutting options are compared for the complete removal of platforms, the most common disposal method, although exceptions are noted for the two other disposal options. Cost comparisons are given as ratios showing differences among cutting options relative to the cost of explosive removals (more detailed cost estimates from previous chapters averaged for different water depths)
|
From page 51... ...
The blast waves from buried detonations differ significantly from the blast waves of traditional in-water detonations used in fish kill experiments in the following ways: · The blast impulse lasts significantly longer because of velocity differences. This raises questions about the 51 validity of existing kill criteria which are all based on observations from controlled, in-water detonation experiments.
|
From page 52... ...
complete removal Dependent on For rigs-to-reefs, type and depth add transportation to site Feasible only in deep water Assumes piles and conductors cut explosively Reliability Current industry Used in shallow Same as Dependent on Potential costs and Same as partial practice for water where large mechanical skill of diver reliability benefits removal, but fewer platforms in water lifting equipment cutting but less increase with depth benefits for larger deeper than 50 feet is not required experience Used for and size of platform platforms in deeper shallow-water water Regarded as most More likely to Improving pile cutting and predictable and cause delays than technology and large caissons flexible explosives shows promisein limited applications Lowest probability Ability to cut of delaying well conductors removal efficiently is questionable 15-foot depth requirement complicates use Human Health and Least health and Lack of Same as Considerable Reduces risk by Same as partial Safety safety risk deployment end mechanical risks inherent simplifying removal .
|
From page 53... ...
. ~ s~gn~cant Remaining structure mitigates habitat loss Remaining structure mitigates habitat loss EFFECTS ON OTHER OCEAN USERS Commercial Fishing Loss of habitat Loss of habitat Possible impact on fish population Loss of habitat Loss of habitat Maintains habitat Negative impact if explosives are used Preserves habitat Negative impact if explosives are used Recreational Fishing Removal of accessible habitat Impact on catchable fish Loss of accessible habitat Loss of accessible Loss of accessible Maintains habitat, habitat habitat but accessibility limited by depth requirement Preserves habitat Creates destinations if accessible sites are used Shrimping No effect on Same as explosives Same as Same as Decreases Same as partial shrimp explosives explosives trawlable removal waters Increases trawlable waters if completely removed No effect in water deeper than 300 feet Commercial Shipping/ Navy/Defense No effect if completely removed or .
|
From page 54... ...
13. The NMFS Observer Program helps to ensure that the efficient use of explosives as constrained by current NMFS, MMS, and Marine Mammal Protection Act regulations is not likely to harm either sea turtle or marine mammal populations or to violate any of the provisions of the Endangered Species Act.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.