The ever more challenging environments in which new wells are to be drilled, the uncertainties of the current market, and the availability of effective secondary and tertiary enhanced recovery (EOR) technologies, make the extension of existing wells' life more advisable than drilling new wells.

To properly and proactively manage the degradation of Well Barrier Elements (WBEs) over time, thus ensuring the extension of wells life, a specific methodology and software have been developed.

The concept of "Wells Life Extension" not only requires to get an adequate knowledge of the current wells integrity status, but also to predict future critical WBE(s) in order to put in place ad-hoc preventive measures.

The methodology described in this paper includes three main phases:

  • Well Integrity Assessment, which evaluates today's well integrity status through a risk-based approach.

  • Estimation of Wells Ageing, which estimates the residual well life based on the understanding of WBEs ageing mechanisms.

  • Definition of Intervention Plan Options, in which wells are classified on the basis of specific parameters, and then prioritized for future interventions through a cost-benefit analysis.

The implementation of such methodology has allowed Customers to find out the most appropriate actions to be carried out on their ageing wells, with the objective of keeping production performances and safely operating the wells in line with the planned targets. Moreover, it has enabled to properly plan such actions over time, on the basis of the risk levels associated to the failure modes of each WBE, thus preventing and mitigating the need of potentially expensive interventions and protracted downtimes.

Furthermore, emergency situations that would even increase costs and/or failures impacts, have been prevented, mitigated, and proper monitoring and maintenance programs have been executed in order to manage risks over time.

In summary, the overall benefit of the presented methodology and software consists in anticipating well integrity issues and extending wells life through a proactive and cost-effective approach, that can enhance assets reliability, improve safety levels and minimize both downtimes and costs associated to WBEs failures.

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