Shallow Water Well Conductor Life Extension Strategy

Shallow Water Well Conductor Life Extension Strategy
November 2013
A. Kumar, S. Abdalla, H. Rosli, H. Howells

A number of shallow water well conductors installed during the 1970s‐1980s especially in the Middle East (Arabian Gulf) region are approaching or have exceeded their design life. Considering the production rates and economic viability for alternative options, there is an increasing need for life extension on these ageing structures.
This however raises the question of structural integrity given the long in‐service usage of these conductors. Age related issues including excessive wall loss and cracking due to corrosion and the associated reduction in strength and fatigue capacity should be addressed.
This paper discusses a strategy for fitness‐for‐service assessment and retrofit repair designs for various anomalies observed on well conductors. A system of management is adopted for a given group of ageing conductors, the system involves a classification scheme based on the conductor and well design and defect type. All conductors within a given classification are pre‐assessed based on the extent of degradation obtained from the measured, empirically modeled or visually assessed inspection records. For every classification, an assessment for generalized strength and stability (in accordance with institute of petroleum guidelines) or localized FEA depending on the anomaly type is carried out for the most degraded conductor identified from pre‐assessment. The detailed assessment results are used to develop a generic conductor repair or risk mitigation plan applicable to all conductors within the classification. Real life examples of the defects encountered and associated repair schemes are described.

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