Dynamic Positioning (DP) systems are becoming more and more used in the Oil and Gas Industry. Over the last decades, the escalation in deep-water exploration and development resulted in an increased number of dynamic positioned rigs. But despite the increasing improvements in technology and capability, there is always a risk of a loss of position due to equipment failures or human errors. In consequence of such event, the DP drilling unit must be able to rapidly shut in the well and disconnect the BOP. Failure during an emergency disconnect procedure may result in damages to the rig, riser, wellhead, and, in worst case, an uncontrolled subsea blowout.

Emergency disconnection may occurs at any time in dynamic positioning drilling rigs, as a result of a sudden blackout or by a quick drive-off, for instance. Because of that, all emergency procedures should be well understood by both DP and drill floor personnel. It is imperative that the risks of a position loss are previously assessed in order to reduce the potential damage caused by a disconnection.

The two most relevant tools for reducing the impact related to the DP System failure are the Well Specific Operating Guidelines (WSOG) and the Emergency Disconnection Guidelines. The WSOG defines four diferent DP Status associated to a specificrig executing a specific operation and using specific equipments and its performance limits - "Normal Status," "Advisory Status," "Yellow Status" and "Red Status". The Emergency Disconnection Guidelines establish the actions in case of reaching each of these status. Emergency Disconnection Guidelines were established for various drilling, completion and workover operations, to be studied and discussed previously activities with BOP / Christmas Tree connected to the wellhead.

The main goal of this paper is to present how the WSOG and the Emergency Disconnection Guidelines work together, bringing statistics and lessons learned of loss of position and emergency disconnections. Additionally, this work suggests emergency disconnect sequence (EDS) options for different operations and BOP configurations (number/type of shear rams available).

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