Wintershall Noth Sea operator: Subsea well clean-up and production optimisation
Challenge
The operator Wintershall planned an intervention on a subsea gas well with the objective of optimising production and accessing additional reservoir intervals.
The operation required cleaning accumulated proppant and sand from the well rathole, while enabling perforation of additional production intervals located below the existing zones.
Several factors increased the operational complexity. The well was expected to produce significant solids, reservoir behaviour was uncertain, and limited deck space on the offshore installation required a compact and carefully engineered surface spread.
Wintershall therefore required a well testing and solids management system capable of safely handling solids production while maintaining stable flow conditions throughout the intervention.
Solution
WFR Oilfield Services deployed a complete surface well testing and solids management spread, engineered to manage solids production while maintaining full operational control of the well.
The system included:
- Emergency shutdown system with ESD valve, control panel, and safety interfaces
- Solids exclusion equipment and wellhead sand catcher
- Choke manifold and surge tank for controlled flow management
- Test separator and flow measurement system
- Dual flare boom with deluge system for safe gas handling
- Transfer pumps and chemical injection system
- Data acquisition system with control cabin and remote monitoring
- Storage and settling tanks for produced fluids
- Heat exchanger and steam generator
- Supporting high- and low-pressure piping, hoses, safety instrumentation, and auxiliary equipment
Additional support systems such as nitrogen and propane quads ensured safe operation and reliable flare performance throughout the operation.
The equipment spread was designed to provide maximum operational capability within the restricted deck space available on the offshore facility.
Execution
Operations were performed in approximately 30 m water depth, with an average crew of four personnel supporting the well clean-up and intervention program.
The system was configured to safely manage solids production while maintaining stable flow conditions, allowing the well clean-out and perforation program to proceed efficiently.
Close coordination between the WFR operations team and the offshore installation ensured that equipment installation, system commissioning, and well intervention activities were carried out safely and efficiently.
The complete operation was executed over 28 days from rig-up to rig-down.
Results
The intervention successfully achieved its operational objectives.
- Well clean-out completed successfully
- Additional production intervals prepared for access
- Safe handling of produced fluids and solids throughout the operation
- Zero non-productive time (NPT) recorded during the project
This project demonstrates WFR’s capability to deliver integrated well testing and solids management solutions for offshore well interventions, even under challenging conditions such as solids production, reservoir uncertainty, and restricted installation space.
The operation now serves as a reference project for similar offshore well intervention and production optimisation activities.
