Decommissioning

We can help you through every step towards decommissioning

Execution Plan 

Creating an execution plan is the first step in the decommissioning process. This plan must include the environmental aspects and field surveys of the project site. This comprehensive plan outlines the timetable for decommissioning tasks, the necessary equipment, and the workforce. The execution plan is necessary for procuring permits from local regulatory agencies to carry out the decommissioning. 

Platform preparation 

To qualify a platform for decommissioning, the tanks, processing equipment, and pipelines must be flushed and cleaned. Platform equipment must be dismantled, which involves cutting pipes and cables between deck modules and separate modules. Below the water’s surface, divers must prepare the jacket for removal by clearing away marine growth and other obstructions. 

Well plugging and abandonment 

The planning phase of well plugging includes: 

• Collection of data 
• Initial inspection 
• Selection of forsaking methods 

Well forsaking workload includes: 

Well entry preparations include filling the well with fluid, removing downhole equipment, washing out the wellbore, plugging open-hole and perforated intervals(s) at the bottom of the well, plugging casing stubs, placing a surface plug, and finally, placing fluid between plugs. 

Conductor elimination 

NDE Offshore adapts the method of conductor removal based on the earlier inspections and precaution plan.

Platform elimination 

Mobilization and demobilization involve various strategies for removing topsides. These can range from lifting the entire structure in one piece to dismantling it into groups of modules, reversing the installation order, or disassembling it into smaller components. The choice of method depends on factors such as available mobilization equipment, personnel, and the installation size. 

Removing the jacket is the second step in the due process. Divers first determine whether to use explosives, mechanical means, torches, or grinding techniques to perform the bottom cuts on the piles. Then, the jacket is removed either in small pieces or as a single lift. Heavy lifting equipment is required to remove the jacket. 

Pipeline and power cable decommissioning 

When decommissioning pipelines or power cables, it must be ensured that all network components are safely dismantled/disabled to prevent a lasting environmental hazard. 

Materials removal and site clearance 

Many platform materials can be recycled and refurbished. If not, they need to be disposed of. In the first step, one must perform a pre-decommissioning analysis: Mapping the location and quantity of waste, pipelines, and power cables. The next step is to do a post-decommissioning analysis that identifies waste left behind during the removal process and notes any environmental damage. Remote Operated Vehicles (ROVs) and divers are subsequently deployed to pinpoint and eliminate any remaining remnants that might impede future utilization of the area. Finally, a comprehensive test trawl confirms the absence of any potential obstructions in the area of the decommissioning.