platform
removal
observer
program

INTRODUCTION

Since 1987, federal regulations required the use of National Marine Fisheries Service (NMFS) approved observers to perform biological monitoring at the explosive removal of oil and gas structures in the U.S. Gulf of Mexico. In that year, the NMFS Platform Removal Observer Program was initiated to meet this requirement. The purpose of the Platform Removal Observer Program is twofold. First, the program functions to protect sea turtles and marine mammals from impacts of underwater explosives used in the platform removal process. Second, the program assesses the impacts of underwater explosives on these protected species. Observers document sightings of sea turtles and marine mammals both before and after detonations, recommend delays in detonating explosives when sea turtles and marine mammals are present, record the condition of observed animals, and coordinate retrieval of impacted animals for medical examination, rehabilitation, and necropsy. From 1989-98 the number of explosive structure removals averaged 98 annually. Because structure installations have balanced removals over the past decade, the total number of structures in the Gulf of Mexico has remained fairly constant at approximately 4,000.

REGULATIONS

• 2006 Biological Opinion
• Table A-1,A-4 (Black & White)
• Table A-1,A-4 (Color)

PROCEDURES FOR SCHEDULING OBSERVERS

1. Within a month or two prior to the platform removal date, contact the Program Manager (phone 409-766-3513; e-mail gregg.gitschlag@noaa.gov) or Logistical Coordinator (phone 409-766-3505; e-mail Megan.Kesterson@noaa.gov).

2. Complete an “Infosheet” and e-mail to gregg.gitschlag@noaa.gov. Be sure to send either an electronic or hard copy of the application you submitted (to Minerals Management Service for removals in federal waters or other government agencies for removals in state waters) for a permit to use explosives. Click on the link to download the Infosheet.

3. A Reimbursable Agreement will be prepared and 24-hour mailed to the individual listed on the Infosheet as the signatory. This agreement assures reimbursement to the National Marine Fisheries Service for costs associated with performing biological monitoring at the structure removal.

4. Sign and return the hard copy of the Reimbursable Agreement via 24-hour mail.

5. Provide periodic updates regarding scheduling of the offshore structure removal to facilitate scheduling of observers.

Intact Offshore Platform

There are numerous types of offshore oil and gas structures including platforms, caissons, submerged wells, and others. Although this program has been named the Platform Removal Observer Program, it really entails all types of offshore oil and gas structures, not just platforms. However, the number of platforms removed with explosives annually exceeds that of other types of structures.

A typical offshore platform has several major components. The “deck” is the uppermost part of the structure located above the sea surface. The deck is welded to the “jacket” which extends from about 10 ft above sea level all the way down to the sea floor.  Steel pilings are driven through the hollow corners of the jacket into the sea floor to depths that may exceed 100 ft. It is these pilings that secure the platform to the sea floor and enable it to withstand the forces of winds and seas. Production platforms also have well conductors which extend down the drill holes. It is through these conductors that oil and gas are extracted from deep within the earth.

HOW ARE OFFSHORE STRUCTURES REMOVED?

Explosives account for roughly 2/3 of all removals. There are a variety of methods and equipment used to perform explosive removal of offshore structures. In the most common platform removal method, torches are used to cut the deck from the jacket which is then lifted from the platform and placed on a materials barge. The interior of the pilings must be clear and unobstructed to permit the placement of explosive charges. Sediment is sometimes found in the lower section of the pilings below the sea floor.   A water jet is used to clear out the sediment.   Explosives are then lowered inside the hollow pilings to a minimum depth of 15 ft below the sea floor which is a requirement of the Minerals Management Service, the agency with jurisdiction over oil and gas operations in federal waters.  The derrick barge is then backed off a safe distance, and explosives are detonated. Pilings and conductors are pulled using the large crane on the barge, and the jacket is then lifted out of the water. Platform components may be returned to shore for scrapping, refurbished for reuse, or they may be returned to the sea at a designated artificial reef site.

MONITORING

In fall of 2006 monitoring protocols were revised in a new Biological Opinion for Explosive Removal of Offshore Structures (EROS). A copy of the complete Biological Opinion appears in the Regulations section of this web site. Monitoring requirements are summarized in Table A-1,A-4 (black and white and color versions are also included in the Regulations section of this web site). All monitoring must be conducted continuously.

Monitoring is performed from vessels, barges, or platforms provided by the oil or gas company responsible for structure removal. No nighttime blasting is permitted. For C4, D2, D4, E2, and E4 mitigation scenarios, a special aerial survey (called a post-post-detonation aerial survey) must be conducted. This must be performed between 2 and 7 days after detonation.

If marine protected species (MPS-sea turtles or marine mammals) are observed within the impact zone during the last 30 minutes of a pre-detonation surface survey, the survey will continue for an additional 30 minutes. This process continues until no MPS are observed within the impact zone. Immediately upon completion of the pre-detonation surface survey, the pre-detonation aerial survey is initiated if one is required. If MPS are observed during the pre-detonation aerial survey, the survey is aborted and opportunistic surface monitoring is conducted for the next 30 minutes. The entire pre-detonation aerial survey is then repeated. This process continues until no MPS are observed within the impact zone during the pre-detonation aerial survey. Immediately upon completion of the pre-detonation aerial survey, if no MPS were observed, then an all clear message will be given and explosives will be detonated immediately. The aerial survey must continue uninterrupted until explosives are detonated. If explosives cannot be detonated for an extensive period of time, then the aerial survey will be terminated. Surface monitoring will continue followed by repeating the entire aerial survey when explosives are ready for detonation. Divers must recover any injured or dead sea turtles or marine mammals observed.
Platforms function as artificial reefs attracting a wide variety of marine life. Whenever possible, impacted fish are opportunistically collected, counted, measured, and identified.

From 1987 through 2006, four sea turtles, all loggerheads (Caretta caretta), were “taken” under these regulations. One was killed, two were injured, and one was stunned. No marine mammals were observed to be injured or killed as a result of the permitted activity. 

PLATFORM OBSERVER POSITION JOB ANNOUNCEMENT (see our jobs page.)

RELATED LITERATURE

(where available online, click on author's name to download PDF file - requires Adobe Acrobat)

• Gitschlag, G. R., Herczeg, B. A. and T. R. Barcak. 1996. Observations of sea turtles and other marine life at the explosive removal of offshore oil and gas structures in the Gulf of Mexico.  Gulf Research Reports 9(4):1-16.
• Gitschlag, G. 1994. NMFS Platform Removal - Sea Turtle Observer Program, p. 274-279. In:  U.S. Department of the Interior, Minerals Management Service. Proceedings; Thirteenth Gulf of Mexico Information Transfer Meeting, December, 1993. U.S. Dept. of the Interior, Minerals Management Service, New Orleans, La, MMS Contract No. 14-35-0001-30665.  OCS Study MMS 94-0061. 508 pp.
• Gitschlag, G. R. and B. A. Herczeg.  1993. Sea turtle observations at explosive removals of energy structures.  Marine Fisheries Review 56(2):1-8.
• Gitschlag, G. R.  1991. Offshore oil and gas structures as sea turtle habitat.  In:  Proceedings of the Eleventh Annual Workshop on Sea Turtle Conservation and Biology.  NOAA Technical Memorandum NMFS-SEFC-302, 195 p.
• Gitschlag, G. R.  1991.   Offshore oil and gas structures and sea turtle habitat.  In:  Abstracts of the 121st Meeting of the American Fisheries Society, 169 p.
• Gitschlag, G. R. and M. L. Renaud. 1989. Sea turtles and the explosive removal of offshore oil and gas structures. pp. 67-68.  In:  Eckert, S. A., K. L. Eckert and T. H. Richardson (Compilers), Proceedings of the Ninth Annual Workshop on Sea Turtle Conservation and Biology, NOAA Technical Memorandum NMFS-SEFC-232, 305 p.
• Klima, E. F., Gitschlag, G. R. and M. L. Renaud.  1988.  Impacts of the explosive removal of offshore petroleum platforms on sea turtles and dolphins.  Marine Fisheries Review 50(3):33-42.

(click on photos below for a larger view)

	Personnel basket used for transferring workers from vessel to platform.
	Offshore workers riding personnel basket.
	Derrick Barge.
	Derrick barge using crane to remove deck of platform.
	Deck lifted from jacket.
	Water jet being used to remove mud from within the platform leg, so that explosives can be lowered 15 feet below the "mud line" or ocean floor.
	Explosives technician preparing a C-4 shaped charge
	Shaped charges ready to be loaded.
	Bulk charges.
	Loading shaped charges into legs.
	Loading bulk charge into conductor.
	Aerial view of job site just prior to blast.  Upper decks of the platform (center of photo) have been removed
	Detonation of explosives.
	Jacket being lifted from water. and welded to the materials barge (right side of photo).  The derrick barge has moved away from the structure.  Work boats (to the left) stand by.

	Helicopters and work boats used to transport observers to work site.  For a variety of reasons relating to offshore logistical costs and the difficulty in predicting schedules for work completion, observers often monitor for several days before explosives are used.

Platforms function as artificial reefs.

Fish kill resulting from underwater explosives.

	NMFS Observer with green sea turtle captured at a platform prior to explosive removal.
	Loggerhead sea turtle with cracked carapace caused by underwater explosions.
	Injured loggerhead sea turtle during rehabilitation.  Note the metal fasteners used to repair damage to the carapace.  The turtle was later released back into the Gulf of Mexico.
Number of individual turtles sighted by MMS lease block, 1986-2003 click on the map to download a full size image Extremely big file! (8839x5783, 7.2 MB)