Life Extension of Aging Petroleum Production Facilities Offshore

Per Otto Selnes, M.Sc. Manager OperationsNorwegian Oil Industry Associationwww.olf.no

Contributor:Gerhard Ersdal, Ph.D.Principal EngineerNorwegian Petroleum Safety Authority

Introduction

• A large part of the Norwegian gas and oil production facilities have reached their initial design life, but the respective fields are still producing substantial levels of hydrocarbons.

• In order to ensure technical and operational integrity of these ageing facilities the Norwegian oil industry Association (OLF) has initiated a project to establish the necessary standards and guidelines for assessing and ensuring safe life extensions.

Background

Technical and operational integrity ofoffshore facilities on the NorwegianContinental Shelf (NCS) is importantfor:

• the safety, health and welfare of offshore employees and their families

• not harming the environment

• making sure that the owners get no interruption of their revenues, nor do the government and the citizens of the country

Complex issue

Age vs status on application for consent• Number of installations on the NCS excl. pipelines:

• Number of consents expiring by end 2015:

• Number of new consents given (Incl. 1 expiring 2015):

• Number of applications being prepared / handled:

• Number of applications due?

• Number of installations shut down:

• Removed/disposed of, additional to the 103

• Disposals approved

103

44

26

7

1

2

5

7

Norwegian pipelinesFirst installations (year) 1971

Total number of items in database : 920

Cumulated length of large pipelines (km): 6 100

Large variations in length, size and design life

Lengths: 23 km - 1 200 km

Diameter (inches): 1’’ – 44’’

Design lifetime (years) : 5 - 50

Scope of workWork divided in two:• Firstly to develop and issue recommended

guidelines, outlining a proposal for the preparation of the application of a new consent;

• Then to develop tools necessary to assess continued safe operation. Split in the following areas:

• Risk management • Working environment • Structural integrity • Technical safety systems • Drilling & well systems• Top side process & utility systems • Transport systems (pipelines etc.) • Sub sea systems

Consent Applications for Lifetime Extension of FacilitiesScope of the OLF guideline for assessments and preparation of applications

Offshore Structures

Published May 2008

Transport Systems

Underwater installations

Drilling and Well Systems

Check List Published in May 2008

OLF guidelineNo. 122

Published in June 2008

Permanente structures

Export and intra field Pipelines and risers.

Drilling systems and Well integrity, including conductors, BOP and down hole equipment

Technical Safety Systems,,Working

Environment and Risk management

Emergency Shutdown, Evacuation, Barriers, Fire and Gas Detection and other safety systems. Living Quarters, Escape Ways, Material and Chemicals Handling , Control Rooms, Man machine interfaces.

Process Systems

Consent Applications for Life Extension of Facilities are submitted to the Petroleum Safety Authority (PSA) Norway and Norwegian Petroleum Directorate (NPD).

Main Document

Sub- Documents

Deliveries

Guideline for the assessment and documentation of service life extension of facilities Three chapters• Outlines a proposal for the preparation of the application

of renewed consent required prior to use of a facility exceeding the current consent period

• The guideline identifies how the operators can assess and document safe operation of facilities for an extended period

• Facilitate the preparation the Application for Consent for Life Extension

Start early• It is recommended to start the evaluation and application

process at least two years prior to the expiry of the current consent period

Technical Safety Systems and Working EnvironmentRisk Management• Gives detailed comments and

recommendations for the assessment of facilities concerning the areas outlined

– recommends Quantitative Risk Analysis (QRA) and necessary sensitivity studies to be updated addressing the scenario and operating conditions envisaged during the life extension period

– Evaluations of factors that may be expected to change over time should be included in the sensitivity evaluations.

Technical Integrity• Normally it is possible to safely operate an installation

beyond its calculated fatigue life by using the inspection results available

• For structural details that can not be inspected, recommendations are given in the standard.

• Piles securing the installation to the sea bed are an example of such structural elements

• Specific requirements to design fatigue factors for calculation of fatigue damage from driving are given, based on driving records

Structural Integrity for Existing Offshore Load-Bearing StructuresNew Norsok Standard• NORSOK N-006 standard gives requirements

for assessment of the structural integrity of offshore structures in-service and for life extension

• NORSOK N-006 is applicable to all types of offshore structures used in the petroleum activities, including bottom founded structuresas well as floating structures.

Drilling & Well SystemsChecklist has been established• General considerations and requirements:

– Brief status on drilling facilities & wells

– Main degradation mechanisms and corresponding control measures relating to “Safety Critical Equipment”

– Well integrity situation and potential changes in the related risk-picture

– Potential well stimulation, intervention & work over methods/ limits

– Future activity level and modification plans– Future capabilities required to monitor, access,

operate, maintain and abandon drilling- and well facilitiesCondition of utility systems to support future D&W activities

– Future capabilities to serve for potential “tie-ins” and specific measures for enhanced petroleum recovery in the area

Top Side Process and Utility SystemsA list of systems that should beaddressed during assessing lifeextension of top side’s process andutility systems has been established• Containing “common factors” to be

considered when evaluating the integrity of process and utility systems.

– Have conditions changed from when the system was designed?

– Will future operations still be within the capabilities of the system?

– Could specific studies be required (list typical studies for individual systems)

Transport and sub sea systemsNorsok standards

Transport Systems (Pipelines Etc.)• The transport system in this context is facilitating transport through

pipelines, risers and loading hoses intra-field, inter-field and as trunk pipelines to shore and onshore.

Sub Sea Systems• Subsea systems are increasingly used on

the Norwegian Continental Shelf and this standard is prepared to support the process of assuring technical integrity of the sub sea system and its elements beyond the original approved service life.

ConclusionThe guidelines, standards and checklists developed through this project will provide valuable assistance to offshore facility owners and authorities when assessing the condition of aging facilities, and if they can be safely operated for a new consent period.