13 minute read
The stepping stones to life extension
Gustavo Adolfo Romero Urdaneta, LATAM Director at Penspen, lays out a guide to the essential steps of formal pipeline life extension.
ow do you justify the operation of pipelines beyond their design life? There are many reasons. For example, increasing the life of the production field, changes in the operational context, or optimising costs and resource utilisation by reuse through a second operator. In addition, being able to process the results from an integrity study to conduct calculations of the remaining life based on the growth of time-dependent defects are other important factors, to name a few. Operating beyond the design life can be done if the pipelines are within a safe operating range for their estimated lifetime and required operating conditions, and if no failures occur that generates adverse consequences. Impacts on human health and safety, the environment, reputation and finances such as production losses, emergency care and recovery costs, are all important considerations. Life extension has become an increasingly attractive option to avoid decommissioning assets, which is a costly and logistically
complicated process. Furthermore, due to the decrease in oil and gas prices, new projects have been postponed or cancelled, which also leads operators to try to keep their assets operating for as long as possible.
For years, the result of the remaining life calculated from integrity projections has been used as justification for extending the life of assets beyond the design life, complemented by a plan of operation (operating within specified limits) and maintenance activities performed during the required life (cathodic protection, coatings, supports, direct and indirect inspections, patrolling, leak barriers, among other activities), to safely guarantee this life extension and refreshing of staff competencies. Despite this, failures unfortunately continue to occur in ageing pipelines that are operating within the remaining life threshold. This is a consequence of inadequate integrity assessment and/or not completing complementary integrity and reliability assurance activities. This can be due to budget, organisational changes, untrained personnel or inadequate change management, combined with the lack of a formal asset integrity management system that includes a process for life extension. API 579 Fitness-For-Service Evaluation states that the remaining life calculated using correlations and defect growth projections obtained during inspections can be used to define appropriate inspection intervals, mitigation, monitoring activities, and remediation needs, and not to provide an estimate of actual time to the failure. This means that in addition to the current integrity condition and remaining life projections, the life extension of a pipeline requires a system to manage the life extension process in a safe, reliable, and cost-effective way within the time required by the organisation and its stakeholders.
Best-in-class operators have already established and developed their pipeline integrity management systems (PIMS) with several cycles of audits, allowing them to maintain the process of continuous improvement of their systems. However, the ageing of pipelines and the process to be implemented when a lifetime extension is required is not included as a formal process in the integrity management system (IMS). At the same time, many regulators have not included the specific requirements that pipeline operators have to comply with when they require life extension, but it is implicit in the paragraphs and items of the rules that require the operator to ensure the integrity and reliability of the pipelines from the start of operation until its abandonment. In addition, the costs for insurance premiums or bonds increase when the pipelines have a low life expectation versus pipelines with an extended life plan.
Background Although ageing asset management is a topic that has been discussed for years, in this article we will focus on the last 10 years and the relevant background regarding the advances and recommendations resulting from the initiatives of government entities, such as the UK and Norway, followed by technical committees of experts, which have helped to create a basis for the life extension of assets. Notable programmes and publications include: ) Between 2010 and 2013, the UK Energy Division of the
Health and Safety Executive (HSE), conducted audits of onshore and offshore assets to review their integrity management systems and asset life extension processes, in order to determine if risks were being managed effectively and to encourage the process of continuous improvement. From these audits, HSE published a report called KP4 (Key Programme 4) in which they indicate that the age of the installation is not necessarily a reliable indicator of the condition or likelihood of the frequency of hydrocarbon leakage but should be referred to other factors such as: leadership and knowledge of the life extension process, the relationship with asset integrity management, obsolescence, audits and monitoring of indicators and data management.
) In 2013, the ISO/TC 67/SC 2 technical committee responsible for discussing the life extension of pipelines noted that operators are applying different approaches to life extension, leading to the inefficient use of resources by both the operator and the authority.
Therefore, the Recommended Practice published by the British Standards Institution (BSI) for Life Extension of ISO/TS 12747 Pipelines was updated in 2013, providing guidance for assessing the feasibility of extending the service life of a (rigid metallic) pipeline system beyond its specified design life. This RP refers to life extension as a modification to the original design without including reclassifications of the maximum allowable operating pressure (MAOP).
) In 2017, after more than 10 years working on and publishing documents related to the life extension of assets, the Norwegian Oil and
Gas Association revised and published the document 122 - Recommended Guidance for Life Extension Management, to establish guidelines for operators who have won
Figure 1. Illustrative diagram of pipeline life extension.
Figure 2. Pipeline life extension (PLE) process.
production licences for fields. This guidance states that two levels should be considered: a first level that focuses on the asset and includes the design life, required life and the need for extension; and a second level that involves the system where the assessments and methodologies for life extension are considered. ) Norway and the UK have already incorporated specific requirements in their regulations to ensure that pipeline operators can continue operating beyond the design life through life extension management as an element of the
IMS. In Norway, it is mandatory to obtain the consent of the regulatory body before extending the useful life of an asset. In the UK, the body regulator sees this life extension as a significant change in the “Safety Case”.
) In late 2020, NOPSEMA (Australia’s Offshore Energy
Regulator) published a guide to promote the industry’s practices to ensure that the risks associated with ageing assets are managed at ranges as low as reasonably practicable (ALARP) in a legislative context of the
Offshore Oil and Gas Greenhouse Gas Safety Act. The age profile of installations in Australia is similar to those in the North Sea, ranging from four years to over 50 years.
) In America, in recent years, countries such as Canada have also begun to incorporate some requirements related to life extension as a process that can be audited through evidence of its effectiveness and follow-up activities. In 2019, the world-class independent regulator
C-NLOPB (Canada-Newfoundland and Labrador Offshore
Petroleum Board) developed a guide to provide additional information and guidance to facility operators on the steps and phases to consider when assessing a Life Extension Plan to maintain the compliance with the regulatory requirements, as well as to ensure that the assets are properly managed and that the necessary improvements are identified and implemented. In
Latin America, the regulations do not set out specific requirements to ensure the safe operation of a pipeline when its lifetime is required to be extended beyond the original design, but rather leave it implicit when they state that the operator shall ensure that pipelines operate safely throughout their lifetime.
State-of-the-art Today, after some years of work and efforts to promote the life extension process as a key element in pipeline integrity management, it is clear that there is still a long way to go, especially in countries where it is not yet mandatory to have a clearly documented life extension process and where the risk of failures continues to grow due to the increasing number of ageing pipelines operating beyond their original design life. For this reason, this article intends to serve as a guide for pipeline operators, regulatory bodies and technical organisations that are interested in knowing a little more about the essential steps required when a formal pipeline life extension process needs to be implemented. The life extension process is an essential part of the PIMS when there are ageing pipelines or when it is required to extend the service life beyond the design life. The success of this process is based on a first level focused on the system that involves the availability of leadership, strategic planning, and information management (storage, visualisation, and digital tools), analysis, monitoring and detection of improvements, and a second level directly related to the studies and activities required to assess the feasibility of the life extension of each pipeline. Figure 2 is a step-bystep flowchart for the implementation of a pipeline life extension process, complemented by the following brief description of each stage.
Stage 0: Application for a pipeline life extension All life extension processes are initially identified at the corporate level as part of the organisation’s strategic plan. Experience indicates that the life extension should be initiated between two to five years before the design life is exceeded. The decision to extend the life of a pipeline cannot be implemented by the technical or operational area alone but must be part of the strategic needs of the organisation at the corporate level. Future plans are established in terms of requirements for demand or changes required to increase or expand the profitability of the business, involving the analysis of the operational costs and investment costs.
During the strategic planning, it is identified whether it is necessary to extend the useful life of any of the pipelines in order to achieve the owners’ and/or stakeholders’ proposed goals, which may include reuse, modernisation, full or partial replacement, refurbishment, remanufacturing and additional safety/process control measures. Sometimes it is necessary with the entry of new investors, who will ask about extension options as a strategy for optimising resources and recovering their investment.
Stage 1: Diagnosis of the current condition There is a consensus that any life extension proposal should start with an initial diagnosis, including a review of the organisation, document management and assessment of the current condition of the pipeline, based on the results of inspection with instrumented tools or through direct assessments whose origin was defined from: ) Risk analysis where the probability of failure due to specific hazards and the consequences that can be generated in each case are defined. This triggers the inspection plan and some risk mitigation activities.
) Integrity assessment that determines the MAOP for each defect, using the recommendations of the Defect
Assessment Manual (PDAM) and the remaining lifetime, using probabilistic defect growth models and cycle counting when it is additionally required to assess the fatigue phenomenon.
) Additionally, the activities necessary to recover or maintain the required integrity and risk for the time set by the operator are identified.
Note: the more information that exists on the condition of the pipeline, the more certain the predictions and possible scenarios for life extension will be.
Stage 2: Life extension needs Once it is confirmed that the pipeline has an acceptable risk and sufficient remaining life under its current conditions to assess the feasibility of life extension, it is determined the specific needs that the operator requires to extend the life of the pipeline safely and reliably. Extending the time beyond the design life (reuse) and keeping the operating conditions within the permitted ranges is normally one of the most common needs; however, it may also include a change in operating conditions (reclassification), as, for example, modification of the flow rate and fluid handled, maximum operating pressure and/or temperature, among others.
In some cases, a change of location, class and/or compliance with new regulatory requirements that would apply during the extension may also be requested. A piping system also includes other elements and fittings in addition to the pipeline sections, which may also require an independent feasibility assessment to confirm their reliability or to identify that they require modifications and/ or upgrades.
Stage 3: Feasibility of the life extension Although pipeline extension is normally the most attractive alternative, a business case or cost benefit study is required that includes, for example, capital expenditure, installation, operation, maintenance, and risk. The Net Present Value (NPV) cost-effectiveness indicator has often been used to determine the most appropriate option by comparing the mitigation cost necessary to achieve the desired life extension with the cost of a new pipeline or replacement of any of its sections and/or parts, and the profitability and revenue for the required extension period. For each alternative proposed as a solution to the life
extension needs, a new risk study should be performed that considers the new scenarios and conditions, with an integrity assessment that simulates and projects the growth of defects under the expected conditions to determine whether the pipeline can achieve the life required by the requested extension process.
It is important to note that the justification for the life extension of a pipeline may also include external and intangible benefits in terms of its benefit to, for example, a community in terms of supplying some energy demand. In some cases, the result may suggest that it is not possible to extend the life and that the most viable option will be the construction of a new pipeline.
Stage 4: Life extension approval Once it is confirmed that the pipeline can be extended beyond its design life in accordance with one of the scenarios that showed the best cost-benefit, a document is created in which the justification, plan of activities required for implementation and plan of monitoring activities to ensure the integrity and risk during the extension of the pipeline’s life is established. Finally, the document must be signed as evidence of approval by the working team assigned by the company for the extension process and senior management. Step 5: Closure and documentation of the process All information created during the extension process shall be included and stored as part of the IMS in a specific section for life extension. In countries where the regulator requests specific compliance requirements, the operator shall ensure that these are included in the proposed documentation and activities. It is recommended to include performance indicators to monitor the implementation of the extension. Some operators keep a record of their ageing assets and the percentage that are operating beyond their design life as a way of classifying their assets and at the same time their condition indicator.
Bibliography
Y-002 Life Extension For Transportation Systems. Norsok Standard (2010). Key Programme 4 (KP4) Ageing and life extension programme Energy Division of HSE’s. Hazardous Installations Directorate (2013). www.hse.gov.uk/offshore/ageing.html PD CEN ISO/TS 12747:2013. Petroleum and Natural Gas Industries – Pipeline Transportation System – Recommendeed Practice for Pipeline Life Extension (2013). API 579-1/ASME FFS-1. Fitness-For-Service (2016). PDAM Joint Industry Project. Pipeline Defect Assessment Manual. Penspen (2016). 122 - Norwegian Oil and Gas Recommended Guidelines for the Management of Life Extension. Norwegian Oil and Gas Association (2017). Selection of the most suitable life extension strategy for ageing offshore assets using a life-cycle cost-benefit analysis approach. Journal of Quality Maintenance Engineering. Vol 24. Issue: 3. I. Animah, M. Shafiee, N. Simms, J. Ahmet, J. Maiti. (2018). C-NLOPB Asset Design Life Extension Program Guideline for Offshore Canada Newfoundland and Labrador (2019). Pipeline Integrity Management System (PIMS). Penspen Model, Penspen (2019). Penspen Asset Life Extension methodology. Penspen (2020). UKOPA/GP/018. Good Practice Guide Remaining Life Assessment (2020).
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