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Ageing and Life Extension Assessment

16 Feb

Life Extension Assessment

Plant equipment, structures and pipelines on reaching their respective design lifetimes are often readily serviceable.  The notion that just because the design lifetime has been reached, the facilities are then no longer serviceable is very strongly challenged.  As an organization, Asset Integrity  Engineering (AIE) has an abundance of practical applications experience which conclusively shows that well-managed and maintained plant equipment, structures and pipeline systems are serviceable essentially on an indefinite basis, only if the said management and maintenance regimes remain in place and that they remain effective and appropriate going forward.

AIE recognize that there is an obligation on the part of all operators to demonstrate robustness of their facilities on an on-going basis, and this of course includes during the period of late operating life including operations beyond the original design lifetime of the facilities. In the context of the latter, the primary requirement is the need to ensure that during the period of extended operational life that the on-going use thereof does not constitute an unacceptable risk condition.

A comprehensive lifetime extension assessment can therefore be performed which should serve to demonstrate that the facilities may be operated safely on an on-going basis until removal from service is either deemed necessary or until the cessation of production date is reached, whichever is occurs first.

Lifetime Extension Assessment: Plant Equipment, Structures and Pipeline Systems

Ageing plant is continually demonstrated to be a major threat leading to incidents or failures; however, we would contend that ‘ageing’ per se is not necessarily about how old the plant equipment, structures or pipeline systems are, but it is everything to do with its overall condition and how this may be changing over time.  Ageing is therefore considered to be the effect which results in progressive deterioration and damage, where the likelihood of failure increases with time in service.  However, just because an item of equipment is old does not necessarily mean that it is significantly deteriorated and damaged, as all types of equipment can be susceptible to varied ‘ageing’ processes.  Chronological age therefore is often considerably less important, but the prevailing rate of deterioration is, given the potential effects that such could have on future safe operations.

Operators are required to anticipate and understand the effects of deterioration or changing conditions associated with ageing and lifetime extension, and be prepared to intervene as necessary to ensure that the facilities business objectives can be satisfied without adversely affecting asset integrity or safety.  AIE has a wealth of experience in assessing such scenarios in its on-going support to its clients.  We take the view that all credible threats shall be considered during the assessment and in this respect, we fully recognize that factors may have changed during the operating lifetime of the facilities where additional credible threats may be at play which were not features of the original design premise at the time.  Prime examples of this are souring of reservoir fluids where sour process conditions were not an original design premise but are a feature of late life operations.  As field development plans evolve, current day production may also be from reservoirs whose fluids compositions are significantly different to those that were considered at the original design stage.  However, whilst these issues should likely have been captured as part of the wider management of change process at the time of their development, it is still important to recognize and capture such issues as part of the lifetime extension assessment process.

AIE conduct lifetime extension assessments in several discrete stages as follows:

  1. Lifetime extension assessment involves the assessment of the design, installation and present integrity status of the facilities being assessed. This necessarily includes reviews of the operational history, and any changes to the original process plant, structures and/or pipeline systems original design. The primary object being to establish the current condition of those facilities and whether there has been a history of issues or failures in the past, and if so, whether or not the primary causal factors were identified and satisfactorily mitigated.
  1. The assessment of all credible threats to the facilities in extended life is an integral part of the lifetime extension assessment. AIE’s approach in this respect is the use of specific risk assessment protocols, where qualitative, semi-quantitative and/or quantitative risk assessment methods are used. However, the choice of method is generally dependent on the specific circumstances, where more significant risk situations may demand a greater level of rigour in order that the outcome may be more reliable and more representative.
  1. The assessment of the time-dependent degradation mechanisms, primarily mechanisms such as corrosion, creep and fatigue threats, to provide accurate estimates in respect of the remaining lifetime of the facilities.
  1. The assessment of any further threats to the facilities (such as cathodic protection remaining life, condition of fabric, dropped objects risks, flow induced vibration, solids erosion and the like) during the extended operating period. Where necessary, the measures to monitor, mitigate or perhaps even remove any threat(s) shall also be considered during the assessment study.
  1. The specification of inspection and monitoring requirements shall also form part of the assessment study to ensure on-going fitness-for-service of the facilities during the future extended period of operation.
  1. Lifetime extension assessment shall also consider the life-cycle costs associated with future operations of the facilities. This is based on the contention that replacement of those existing facilities is an option and that use beyond the original design lifetime may be so costly as to preclude this as a viable business proposition. The contention being that more aged infrastructure may require a higher level of management funding to maintain in safe operation relative to that for new infrastructure. However, this must be balanced by the high up-front costs associated with the investment in new infrastructure.
  1. Obsolescence is often a problem in late life operations. It becomes manifest when the facilities and/or systems are no longer useful or reliable and is often characterized by the absence of critical spares and technical support in the supply chain. AIE are well experienced in this issue which we also regularly encounter during our computerized maintenance management system (CMMS) build service to clients. We will undertake detailed investigations in order that potential obsolescence issues that could affect the safe and reliable on-going use of the facilities are known and understood so that suitable plans can thereafter be developed to manage and/or rectify the situation.

The lifetime extension assessment works shall be used to formulate a detailed activity plan for the on-going management of the facilities risks going forward, providing that it is proven during the assessment that the risks associated with the operation of those facilities can likely remain as low as reasonably practicable (ALARP) during the period of extended operational service.  The outputs therefrom are therefore an integral part of the integrity management strategy for the facilities going forward into extended operational life.   Such outputs would include, but would not be strictly limited to the performance of risk-based control activities (inspection, monitoring etc.), maintenance, testing and in monitoring performance and/or strategy effectiveness.  These would be effected using leading and lagging performance metrics and risk factors where these latter planned activities provide the basis upon which on-going extended life operations can be justified.

We aim to execute such assessment works through active engagement with, and participation of, the client specialists, subject matter experts and/or technical authorities as is appropriate.  Whilst we recognize that a large part of the assessment works can be undertaken in isolation, using AIE engineering specialists, the active engagement and participation of the client specialists, subject matter experts and/or technical authorities is vitally important as the specific plant knowledge and history would not likely be available to AIE otherwise.  A series of specific workshops would therefore be conducted whereby the key issues would be discussed and captured therein.  These would also serve as a vital vehicle for confirmation of all assumptions made during the assessments and where any potential obstacles to lifetime extension can be raised, discussed and either confirmed or discounted.

AIE is an independent, highly skilled, integrity services provider and possesses the necessary skills base, experience, and competencies to conduct such assessment works on behalf of its clients.  Our experience in lifetime extension assessment of plant facilities and infrastructure is considerable, as is that for our wider portfolio of services in the field of integrity management for aged assets.  We are a key service provider throughout the MENA region and overseas.  We constantly strive to maximize the value that we add to our client’s business activities and our primary goal is to always aim to provide services that surpass our client’s expectations.

If you would like to understand how our integrity service team can support your requirements in this area, please visit our contact us page and we will promptly respond to your inquiry.

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