Asset Integrity Assessment and Management Program for Life Preservation of a Purpose Built FPSO and Associated Subsea System Facilities

Abstract

Floating facilities for production, storage and offtake (FPSO) and other offshore production facilities have been used safely and reliably throughout the oil industry for many years. Asset Integrity is increasingly important to optimising safety and operational life and asset performance efficiency. Operators need to comply with Corporate, Regulatory and Certification requirements but recognise that developing and managing an effective and compliant Asset Integrity Management System is both time consuming and costly. Review of operational history of existing large FPSOs around the world indicated low confidence in operational life expectancy and to achieve the design life without possible dry docking or major repair. FPSOs have certain loading characteristics and damage consequences that make them different to other offshore installations and conventional ships, and often more challenging to maintain and operate. Maintenance and inspection campaigns are important inputs in the Asset Integrity Management (AIM) system of FPSOs and other floating offshore facilities. Considering that the unit shall stay on site during the whole life of the field, where disconnection or the removal of the mooring system is not planned, a comprehensive methodology for the asset integrity management, survey, inspection, testing, maintenance and repair of the unit during this period needs to be developed and subject to review based on the results of the scheduled inspections and audits. So as well as class and statutory requirements, inspection and survey, maintenance and repair plans should reflect the required availability, functionality, survivability and durability of the unit, giving due regard to its field life, as part of the safety management of the facility. Risk Based Integrity management methodology has been adopted in several projects and is an important tool to establish a rational inspection campaign for structural components, mainly for those located in areas where access is critical and operational constraints are an important parameter. This paper gives an overview of the challenges and discusses various aspects of ageing related to FPSO facilities, represented risk to the integrity of a facility and the required procedures and reassessment criteria for maintaining the structural integrity. This paper also provides an overall view on the regulatory requirements, documentation and calibrations/validations of the original design values to maintain the safety level by means of a maintenance and inspection programs balancing the ageing mechanisms and improving the reliability of assessment results. A brief summary of an example project of an asset integrity assessment and management program for life preservation of a purpose built FPSO and associated subsea system facilities is presented.