BOEM provides an analysis of the subsurface to satisfy various regulatory requirements that accompany the approval process for a well on the OCS. BOEM calculates the Worst-Case Discharge (WCD) for proposed drilling operations by estimating the daily rate of an uncontrolled flow of natural gas and oil from all producible reservoirs into the open wellbore. BOEM also evaluates subsurface drilling hazards and conducts a broaching analysis, when necessary, for proposed wells on the OCS.
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).
- 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
- 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
- NTL 2015-N01 FAQ - Frequently Asked Question Information Sheet
BOEM conducts Regulatory Reviews in order to evaluate drilling hazards posed by surface and subsurface geologic conditions and man-made obstructions (30 CFR 550.201 - 207). In addition, reviews are performed to evaluate shallow hazards (seafloor and near seafloor) on operators’ applications for right of way and laying pipelines permits (30 CFR 250.1007 (5)). These reviews are conducted under an OCS operators’ Plans of Exploration (POE), Development and Operations Coordination Document (DOCD), or Application for Permit to Drill (APD). The regulatory reviews provide a detailed evaluation of an operators' geohazards analysis and are used to determine mitigations to be applied to the plans and permits that are issued. These reviews include verification of an operator’s interpretations, identifications, and assessments of potential geohazards in the area affected by drilling, installation of structures, laying pipelines and other ancillary activities related to the plans.
BOEM geoscientists also conduct evaluations (broaching analysis) in support of BSEE reviews and approvals of operators’ APDs. The integrity of the well design is evaluated by BSEE and a broaching analysis is conducted if a determination is made that the well may fail at a certain casing point. The broaching analysis evaluates subsurface stratigraphic and structural conditions to determine if escaping hydrocarbons from the failed casing shoe will be trapped in the formations or potentially reach the seafloor at some point.
Alaska Region
- NTL 2005-A02 - Shallow Hazards Program
- NTL 2005 -A01 - Shallow Hazards Program
Atlantic Region
- There are currently no active leases in the Atlantic OCS Region and no information is available.
Gulf of America Region
- Summary of Seafloor Broaching Project (2015-2019)
- Summary Depositional History of the Mississippi Fan (BOEM 2019-048)
- Executive Summary; Shallow Water Flow Mapping Project (BOEM 2019-048)
- Shallow Water Flows in the Gulf (BOEM Report March 2015)
- Study of Shallow Water Flow Prediction using Multicomponent Seismic Data (TAP Project Number 381)
- NTL 2008-G05 - Shallow Hazards Program
Pacific Region
- NTL 2006-P01 - Shallow Hazards Program