WellScreen
Background
WellScreen was originally developed in 2018 for screening the fatigue life of subsea wellheads in the North Sea and was later expanded to have a more global reach. The screening tool performs an accurate and rapid assessment of wellhead fatigue using a parametric finite element model of the riser, wellhead and conductor with a soil/cement foundation.
The initial developments focused on fatigue damaged generated by wave action and vessel motions. However, during the development for global applications, assessments of Vortex Induced Vibration (VIV) damage was also incorporated in 2021. Furthermore, modelling improvements were made to provide a better representation of the surface casing and possible cement level variations on full hole or slim hole configurations.
Applications
WellScreen provides a process for rapid wellhead fatigue screening covering the full life cycle of each well considered from initial drilling to final abandonment as follows:
- Installation (drilling)
- Completion
- Redevelopment (de-completion, sidetrack and recompilation)
- Abandonment (P&A)
Early rig selection
The screening tool can quickly assist early rig selection. Assessment of wellhead fatigue can be performed for all possible vessel options before contract award. This approach is very quick and cost-effective - enabling feasibility to be established for all considered rigs. Thus avoiding the high cost of incorrect rig selection for the proposed operation which may result in significantly higher equipment costs. Or having to employ expensive load relief systems (i.e. BOP tethers).
New wells
For new wells, system design evaluation is readily achieved through rapid and cost-effective fatigue screening. Therefore, multiple options for wellhead/conductor and Tree equipment selection can be considered in advance of procurement. This provides invaluable guidance in selecting the right equipment which is fit for purpose and commercially sound.
Workover and P&A campaigns
For workover and P&A campaigns on older wells, rapid fatigue screening can be performed to assess critical wells. This means that multiple wells are screened for wellhead fatigue and only problematic wells or weak wells are identified for detailed Global Riser Analysis.
Cost & Time Benefits
In practice, WellScreen has significant commercial benefits. On one P&A campaign, 26 wells were screened and only one well required detailed analysis to maximise its fatigue life. On another project, 33 wells were screened, with 4 wells requiring further in depth analysis.
Form more information, please contact AS Mosley directly.
