Abstract

This paper summarizes the proposed API Recommended Practice for Structural Integrity Management (RP 2SIM) for fixed offshore platforms. The proposed RP has been under development for the past two years and pending API approval, should be published within the next year. The new RP will serve as a companion to API RP 2A, which will be restructured to focus solely on the engineering of new platforms, with the new document focused on the integrity management of existing platforms.

RP 2SIM will contain updated versions of the above and below water Structural Survey (Section 14) and Platform Assessment (Section 17) from the present RP 2A. The document will also contain guidance on data collection, riskbased inspection (RBI), assessment methods, assessment criteria, damage assessment, upgrades and repairs, and platform decommissioning. It is being written in a manner to make it consistent with similar ISO guidance on SIM, and will provide considerably more in-depth guidance for maintaining existing platforms than is presently available in RP 2A. RP 2SIM will be a timely addition to the API family of RPs for offshore platforms.

Background

The design process has matured since platforms were first installed in the late 1940's. Figure 1 shows the evolution of offshore platform design in the Gulf of Mexico that has been based upon a combination of events such as hurricanes, development of standards such as API, and advances in industry practices. The first edition of API RP 2A used for designing fixed offshore platforms was published in 1969. Platforms built prior to this were designed to a wide variety of criteria and fabrication techniques; typically dependent upon the operator or the engineering/fabrication contractor. During the 1970's better application of design practices ensured higher engineering standards, until the first modern platforms began to be installed in the late 1970's using a consistent design recipe then available in RP 2A. Platforms installed since the early 1980's provide a more robust design and incorporate many of the lessons learned during the design, installation and operation of earlier platforms.

During the early 1990's an API task group developed RP 2A Section 17 for the Assessment of Existing Platforms. The guidance provided a process for evaluating older, existing, platforms to ensure that they were fit-for-purpose, including the use of metocean criteria that was lower than that for design of new platforms. Eventually adopted by API RP 2A in 1996, Section 17 has provided a process by which engineers can ensure fitness-for-purpose of existing offshore structures.

In the mid-1990's the International Standardization Organization (ISO) developed draft guideline 19902 for Fixed Steel Platforms, which contains recommendations for Structural Integrity Management (SIM). Some of the ISO SIM is similar to RP 2A Section 17, although the metocean acceptance criteria are specific for different worldwide regions as defined in Regional Annexes. The ISO SIM recommendations have enhanced the Section 17 principles and made the SIM process self contained; including Data gathering, Evaluation of the data, development of a SIM Strategy and the implementation of a SIM Program.

This content is only available via PDF.
You can access this article if you purchase or spend a download.