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UNITED STATES DEPARTMENT OF THE INTERIOR
MINERALS MANAGEMENT SERVICE
GULF OF MEXICO OCS REGION
| NTL No. 2003-G16 |
Effective Date:
August 15, 2003
Expiration Date: July 1, 2006 |
NOTICE TO LESSEES AND OPERATORS OF FEDERAL OIL AND GAS LEASES
AND PIPELINE RIGHT-OF-WAY HOLDERS
ON THE OUTER CONTINENTAL SHELF (OCS), GULF OF MEXICO OCS REGION
Assessment of Existing OCS Platforms
The Minerals Management Service (MMS) regulations at 30 CFR 250.900(g)
require that all OCS platforms be designed, fabricated, and installed in accordance with
the provisions of the American Petroleum Institute Recommended Practice for Planning, Designing,
and Constructing Fixed Offshore Platforms – Working Stress Design, Twenty-First Edition,
December 2000 (API RP 2A-WSD). Section 17.2 of API RP 2A-WSD states that an existing
platform should undergo an assessment process if one or more of the conditions noted in
sections 17.2.1 through 17.2.5 exist. Under this authority, the MMS Gulf of Mexico OCS
Region (GOMR) has determined that each existing OCS platform in the Gulf of Mexico that
has been in service for more than five years must now undergo such an assessment. This
Notice to Lessees and Operators and Pipeline Right-of-way Holders (NTL) provides a timetable
and guidance on how you will conduct these platform assessments.
Conduct these platform assessments using the following five-step process:
1. Exposure Category Evaluation
By June 1, 2004, using its life safety level and the consequence of failure level, determine the exposure category (see Section 1.7 of API RP 2A-WSD) of each of your OCS platforms in the Gulf of Mexico. The consequence of failure level is determined by the number and type of wells, production facilities, and pipelines supported by the platform.
Although most platforms in the Gulf of Mexico OCS have an exposure category of L-2 or L-3, some platforms have an exposure category of L-1. Often, the pipelines supported by the platform will determine that a platform has an L-1 exposure category.
The L-3 exposure category is limited to those platforms that are unmanned and meet the low-consequence conditions found in Section 1.7.2.c of API RP 2A-WSD. In general, platforms that are (1) in more than 100 feet of water, (2) support six or more well completions, or (3) have more than two pieces of production equipment have an exposure category of either L-1 or L-2. The wells, facilities, and pipelines supported by a platform determine whether its exposure category is L-1 or L-2.
2. Platform Assessment Initiator Determination
By June 1, 2004, for each of your OCS platforms in the Gulf of Mexico, determine if a platform assessment is required, based on of the five platform assessment initiators listed in Sections 17.2.1 through 17.2.5 of API RP 2A-WSD. These initiators are
- Addition of personnel,
- Addition of facilities,
- Increased loading on the structure,
- Inadequate deck height for its exposure category, and
- Damage found during inspections.
Platforms that do not trigger any initiators fulfill the assessment requirement. Continue the assessment of each platform that triggers one or more of these platform assessment initiators.
3. Design Level Analysis
By June 1, 2005, for each of your OCS platforms in the Gulf of Mexico that triggered one or more assessment initiators, use the design level analysis procedures in Sections 17.7.2 of API RP 2A-WSD to assess the platform. Platforms that pass the design level analysis fulfill the assessment requirement. Continue the assessment of each platform that does not pass the design level analysis.
You may omit the design level analysis if you choose to conduct an ultimate strength analysis (see below). Also, please note that Section C17.5 (Assessment Process) of API RP 2A-WSD provides three acceptable alternative assessment procedures.
4. Ultimate Strength Analysis
By June 1, 2006, for each of your OCS platforms in the Gulf of Mexico (1) that triggered one or more platform assessment initiators, and (2) for which either you did not conduct a design level analysis, or you did conduct a design level analysis and the platform did not pass, use the ultimate strength analysis procedures in Sections 17.7.3 of API RP 2A-WSD to demonstrate whether the platform has adequate strength and stability to survive the ultimate strength loading criteria set forth in Sections 17.5 and 17.6 of API RP 2A-WSD. Platforms that pass the ultimate strength analysis fulfill the assessment requirement.
5. Mitigation Alternatives
By November 1, 2006, each OCS platform that does not meet the assessment requirements through screening, design level analysis, or ultimate strength analysis needs mitigation actions. Mitigation actions are defined in Section 17.8 of API RP 2A-WSD as modifications or operational procedures that reduce loads, increase capacities, or reduce exposure.
Contact
Please address any questions regarding assessment of existing OCS platforms to Mr. Tommy Laurendine of the MMS Gulf of Mexico OCS Region, Office of Technical and Structural Support, by telephone at (504) 736-5709 or by e-mail at tommy.laurendine@mms.gov.
Paperwork Reduction Act of 1995 (PRA) Statement
The information collection provisions referred to in this NTL are intended to provide clarification, description, or interpretation of requirements in 30 CFR 250, subpart I. The Office of Management and Budget (OMB) has approved the information collection requirements in these regulations and assigned OMB Control Number 1010-0058. This NTL does not impose additional information collection requirements subject to the PRA.
Chris C. Oynes
Regional Director
