Deepwater Drilling: contingency planning and standards

Published on: 17 June 2015

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The Macondo Gulf of Mexico disaster had a profound and transformative effect on our industry. Along with our peers, Tullow has been taking steps to ensure such a tragedy never happens again and that lessons are learned and implemented.

The statistical probability of losing control of a well is small as there are numerous checks and balances in place in both the design and operational phases that should prevent it happening. The loss of control of a well can only happen if we fail to observe our basic procedures at several different stages, and we manage our business to ensure this does not happen. However, as demonstrated by Macondo, unexpected events can still occur so, as a responsible and safety conscious operator, we have developed a contingency plan to recover the situation if the worst-case happens.

Our emergency response plan is run by our Well Engineering team and provides a way of regaining control by drilling a relief well, and every subsea well drilled by Tullow has a relief well plan in place prior to spud. However, drilling these wells can take between 100 and 140 days to complete. So we have invested in securing access to equipment that will allow us to cap the well and stem the flow of hydrocarbons within a likely maximum of 40 days. This timescale applies where debris clearance is required but in a simpler recovery scenario, where the rig is still fully functional and drilling systems remain in place, the well could be capped in a much reduced time-frame. Once the cap is in place, it prevents further flow until the relief well is completed, and also allows safe re-entry to the well to put in place permanent abandonment operations if the circumstances require it.

Tullow has a contract in place with Wild Well Control (WWC) to provide access to two capping stacks and also to provide expert support for Well Control incidents. In addition to the capping stack contract, Tullow has an additional contract with Oil Spill Response Limited for a readily accessible and easily mobilised oil spill dispersant stockpile that has been made available to the industry. The Global Dispersant Stockpile is large enough to provide for serious oil spill incidents and has been spread globally at different locations for a more local, faster response to any oil spills. These contracts, along with our arrangements with numerous other service providers mean we have immediate access to all the equipment and services that we could foreseeably need in the event of the loss of control of a well. 

The precise details of our processes are set out in the Subsea Well Containment Emergency Response Plan. This includes the development and training of the Subsea Well Containment Team and regular exercises to test the robustness of our systems.  We have held two full-scale exercises over the last two years based on loss of containment scenarios in Mauritania and Norway and we continue to hold regular exercises. We are focused on ensuring that our approach keeps up with changes in equipment, technology, personnel or legislation. We also ensure that the lessons learned are captured in the feedback process and applied to subsequent exercises.  

We include third party organizations in our Well Control Emergency Response Planning (WCERP) and emergency exercises to provide external input into guidelines, standards and policies. This has helped to improve the overall cohesiveness of Tullow’s response and the application of their expert knowledge and experience has made our exercises more realistic. 

This work has improved all aspects of our readiness and response. The most significant areas of improvement have been a refined and simplified set of WCERP documents and the development of a common operating picture that maps emergency plans against spatially relevant information. We have also developed specialist knowledge of capping equipment and emergency response resource requirements. In particular, we have a detailed understanding of both the numbers of people we need on the ground for general support and the more specialist skills we require.

Around 80% of the man hours worked on Tullow activities are undertaken by contractors, so managing safety risks through our suppliers and their workers is of paramount importance. Our contracts with rig owners require them to have a Safety Case that complies with the International Association of Drilling Contractors (IADC) standard as a minimum.  We also require contractors’ Safety Management Systems to be audited and do disqualify contractors during the tender process if their System is inadequate or if the competency of their personnel does not meet our required standards.
 
We align with the Tullow Integrated Management System and ensure our own processes and standards are observed. At the heart of these standards is the Well Control Standard which itself is closely aligned to industry standards including American Petroleum Institute’s Standard 53 (APIS53). This details Blowout Prevention Equipment Systems for Drilling Wells with a focus on standardising operating requirements and prioritising preventive maintenance, inspections and testing.

All this underlines that we recognise that losing control of a well is one of the largest risks in our portfolio and we use all these measures to ensure we remain focused on managing and reducing this risk.

 

Page last updated: 17 June 2015