Abstract

Oil & Gas Companies design, construct and operate wells in such a way to ensure isolation of reservoir fluids from the surface environment and other underground layers, and to avoid potentially severe HSE and economic consequences deriving from their release.

To keep such fluids under control - thus ensuring well integrity - Operators establish well control policies that require maintaining, at all times, at least two independent barriers in place. However, the elements comprising well barriers may become impaired, due to improper construction operations and/or degradation over the well life.

An innovative risk-based Well Integrity Management methodology has been developed for a gas storage field and then extended to production fields. It complies with the ISO TS 16530-2 "Well Integrity for the Operational Phase", and enables proactive management through the anticipation of well integrity issues, by estimating the residual well life on the basis of the expected well barriers degradation.

A failure mode analysis technique represents the basis of the methodology. The Operator's experience for the specific field being studied is analysed to extrapolate the well barriers elements degradation factors, which are used as input to the above estimation. Dedicated software has been developed to effectively support the estimation process.

The proactive management approach deriving from the methodology application has enabled to:

  1. Develop a clear understanding of potential well integrity issues over time, and ensure the management of the related risks

  2. Effectively support the decision-making process, through the identification of priorities for well integrity interventions

  3. Prepare operational plans for proper monitoring and maintenance of well barriers functionality.

As such, the methodology has allowed enhancing the reliability of assets and ensuring high safety levels, while minimizing downtime and reducing costs.

This paper describes the principles of the innovative methodology applied, and highlights the main characteristics of the related software.

Keywords:
operational safety, proactive management, performance standard, wbe, identification, assessment, information, preliminary well criticality level, well barrier element, well integrity
Subjects:
Wellbore Design, Safety, Wellbore integrity, Operational safety, Well Integrity
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2015. Offshore Mediterranean Conference
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