Subsea Wellhead System Life Extension

Life extension of subsea wells is proving to be a cost effective method of maximising production in fields that are aging and possibly approaching the end of their design life. 2H can provide detailed assessments of a subsea well’s current condition and potential future use to determine if life extension is possible. 

Our assessments consider the asset’s operational history since installation and detail its residual strength and fatigue capacity to help decision making regarding re-entry. To achieve this, we work closely with our clients to gather as much data as possible on the well’s operational history, including as-built design records and surveys detailing any degradation. We then define and deliver a scope of work that is appropriate to the specific well. The outcomes of the assessment are used to define guidance and recommendations for the planned operations, which may include the use of structural monitoring or in extreme cases, wellhead load relief systems.

Key Services

• Analysis of previously accumulated fatigue damage
• Calculation of fatigue damage from future drilling and completion operations
• selection of a suitable drilling vessel and riser system
• Definition of optimum operating criteria to minimise further fatigue damage
• Monitoring system design and implementation
• Wellhead system model calibration and fatigue re-estimation
• Evaluation and recommendation of mitigation measures to reduce wellhead system loads

Project Experience

• Offshore Ireland – Workover operations on 30” conductor wells
• North Sea – Sidetrack drilling on tieback wells
• UK continental shelf – Re-drilling of template wells
• Offshore West of Shetland – Conversion of appraisal wells to production wells
• Offshore Australia – Shallow water drilling with 5^th generation vessels on the NWS