Worst Case Discharge Determination

Overview

Worst Case Discharge (WCD) for exploratory and development drilling operations is the daily rate of an uncontrolled flow of natural gas and oil from all producible reservoirs into the open wellbore. The package of reservoirs exposed to an open borehole with the greatest discharge potential is considered the worst case discharge scenario.

Operators must submit WCD calculated volumes, and associated data according to NTL 2015-N01(Information Requirements for Exploration Plans, Development and Production Plans, and Development Operations Coordination Documents on the OCS for Worst Case Discharge and Blowout Scenarios) and the associated frequently asked questions as part of every Exploration Plan and every Development Operations Coordination Document/Development and Production Plan.

Each Region is responsible for WCD verifications and decision documentation associated with plans under their jurisdictions. Resource Evaluation geoscientists and engineers independently verify the validity of the volume calculations, assumptions, and analogs used by the operator for the WCD. The BOEM Worst Case Discharge model outputs are also used by BSEE in oil spill response plans and cap and stack or cap and containment decisions made as part of the Application for Permit to Drill process (a BSEE responsibility).

Resources and Publications

• WCD Literature Review - Research and Development on Critical (Sonic) Flow of Multiphase Fluids through Wellbores in Support of Worst-Case-Discharge Analysis for Offshore Wells
• CFD Modeling Report - Research and Development on Critical (Sonic) Flow of Multiphase Fluids through Wellbores in Support of Worst-Case-Discharge Analysis for Offshore Wells
• Experimental Report - Research and Development on Critical (Sonic) Flow of Multiphase Fluids through Wellbores in Support of Worst-Case Discharge Analysis for Offshore Wells
• Interim Report 2018 - Development and Improvement of Flow Models Applied to Multiphase Flows in Large-Diameter Pipes and High-Velocity Flows
• BOEM M15PC00007 - Experimental Investigation of Two-Phase Flows in Large-Diameter Pipes and Evaluation of Flow Models Applied to Worst-Case-Discharge Calculations
• BOEM 2015-N01 - Information Requirements for Exploration Plans, Development and Production Plans, and Development Operations Coordination Documents on the OCS for Worst Case Discharge and Blowout Scenarios
• BOEM 2015-N01 FAQ - Frequently Asked Question Information Sheet