Plume Analysis Establishes Safe Work Zone and Confirms Well-Access forSubsea Capping Equipment Installation

摘要

The scope of this paper is to present the benefits of incorporating plume analysis studies into source controlemergency response planning (SCERP) and preparations, prior to a blowout event. By using modeling andengineering analysis as part of the SCERP, plume studies can improve the likelihood of successful cappingstack installation efforts during a blowout. A blowout is a low probability but potentially high impact event that could occur during any well'slife. Immediate action is required to bring the well back under control and minimize the consequences.Protocols for dealing with a blowout are usually outlined in an emergency response plan (ERP) developedahead of time. In the case of subsea wells, a subset of an ERP is a source control emergency responseplan (SCERP) focused on how to halt the flow of hydrocarbons from the well. As described by theInternational Association of Oil and Gas Producers (IOGP) planning guide published in January 2019,multiple engineering assessments are recommended in support of the SCERP, including plume studies.Generally, Computational Fluid Dynamics (CFD) or similar tools are used to carry out the plume studies.Plume studies model the subsea release, comprised of hydrocarbons (oil and/or gas) and water, and trackthe dispersion of the hydrocarbons from the seabed through the water column to the sea surface. The surfaceconcentrations of hydrocarbons pose a flammable threat above the water surface and hence, are a threat tothe response teams. The plume modelling also identifies whether vertical well access is compromised; animportant consideration for capping stack installation. Further, interaction between the blowout flow andthe capping stack during its installation can complicate and threaten a successful intervention. The subseaplume studies can also examine such interaction.