The interruption of gas or oil supply due damage caused by an accident or corrosion to of a pipeline are high. The state of readiness for an emergency repair system to rectify the loss of serviceability of a pipeline is therefore recognised as a critical aspect in achieving availability of re-supply. A specfic Repair manual establishes the basis of the selected repair contractors detailed procedures and highlights those areas where it is anticipated that equipment specific detail will be required from the contractor based on his own specific equipment. Detailed procedures should be fully developed and approved in advance of an emergency event.
Assessment Overview
The actions that should be taken once the operator has reason to believe that the pipeline has experienced damage or is leaking should follow a sequence of decisions and procedures by the operator's emergency project coordinator. These decisions would proberly be based on information subject to some uncertainty.
The priorities would be:
- Take steps to minimise the risk of human life;
- To comply with legislative requirements.
- To minimise loss of time which may arise through indecision or incorrect decision;
- To fully utilise the equipment and expertise available in order to minimise response times;
- To minimise unnecessary or over-reactive actions;
Sub sea damage may be reported as a strong possibility following an incident such as a reported impact near the pipeline route (e.g. sunken vessel or dragged anchor), without any indication that a leak has occurred.
The initial ROV survey will need to confirm the extent of the damage and the risks involved for further inspection or remedial work that can be safely carried out using divers.
The following points would need to be considered before approach to a pipeline incident:
- How was the initial incident reported (Platform/terminal leak detection)
- Observation made with vessel anchoring in restricted area.
- Aeroplane/Helicopter flypasts reports surface bubbles.
- ROV/Diver Inspection on pipeline.
The headings below represent actions and procedures that might be implemented during the Initial inspection/investigation of an incident on a submerged pipeline. The need might arise from the initial inspection of a incident that the below criteria have to be met before any further work can be carried out, or that more information can be gained safely for a engineering assessment by applying some, or all of the following tasks:
- Pipeline Isolations.
- Pipeline depressurisation.
- Pipeline Flooding.
- Pipeline excavation.
- Concrete coating removal.
- Protective coating removal.
- Ovality pipeline measuring.
- Pipeline deflection measurement.
- Pipeline cutting.
Pipeline Damage Assessment (Next)
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