Worst Case Discharge
Encyclopedia
Worst Case Discharge is a calculation used by the Bureau of Ocean Energy Management, Regulation and Enforcement to determine the maximum flow rate for an offshore oil well
in the event of an oil spill
. WCD first came to prominence in the aftermath of the Deepwater Horizon Oil Spill
to determine potential liability if another oil spill were to occur.
though the first actual was performed in August 2010 to model the Deepwater Horizon spill. In January 2011, several major oil and gas companies were allowed to resume deepwater drilling while Worst Case Discharge studies were being completed.
In March 2011, the Worst Case Discharge study on the Deepwater Horizon Oil Spill was released to the public in the Flow Rate Technical Group
final report.
is the method used by the BOEMRE to calculate WCD as simulation can accurately model the rapid changes near well bore that occur in an uncontrolled blow out event. The BOEMRE currently uses the Merlin finite difference
simulator and nodal analysis
package to perform all WCD studies since using the software to determine the official flow rate for the Deepwater Horizon Oil Spill
. Engineers typically use radial modeling to calculate WCD as a radial model can employ sufficiently small grid cell sizes around the well bore that increase in volume as cells extend into the aquifer
.
Offshore drilling
Offshore drilling refers to a mechanical process where a wellbore is drilled through the seabed. It is typically carried out in order to explore for and subsequently produce hydrocarbons which lie in rock formations beneath the seabed...
in the event of an oil spill
Oil spill
An oil spill is the release of a liquid petroleum hydrocarbon into the environment, especially marine areas, due to human activity, and is a form of pollution. The term is mostly used to describe marine oil spills, where oil is released into the ocean or coastal waters...
. WCD first came to prominence in the aftermath of the Deepwater Horizon Oil Spill
Deepwater Horizon oil spill
The Deepwater Horizon oil spill is an oil spill in the Gulf of Mexico which flowed unabated for three months in 2010, and continues to leak fresh oil. It is the largest accidental marine oil spill in the history of the petroleum industry...
to determine potential liability if another oil spill were to occur.
History
The now defunct Mineral Management Service planned to implement Worst Case Discharge studies before the Deepwater Horizon Oil SpillDeepwater Horizon oil spill
The Deepwater Horizon oil spill is an oil spill in the Gulf of Mexico which flowed unabated for three months in 2010, and continues to leak fresh oil. It is the largest accidental marine oil spill in the history of the petroleum industry...
though the first actual was performed in August 2010 to model the Deepwater Horizon spill. In January 2011, several major oil and gas companies were allowed to resume deepwater drilling while Worst Case Discharge studies were being completed.
In March 2011, the Worst Case Discharge study on the Deepwater Horizon Oil Spill was released to the public in the Flow Rate Technical Group
Flow Rate Technical Group
The Flow Rate Technical Group is a group of scientists and engineers from the United States federal government, universities, and research institutions created May 19, 2010, for an official scientific-based estimate of the flow of oil in the Deepwater Horizon oil spill. It issued an interim report...
final report.
Analytical equations
Analytical equations are the simplest method for calculating WCD. However analytical equations cannot account for the rapid change in relative permeability and saturation near the well bore and have been replaced by simulation modeling.Reservoir simulation
Reservoir simulationReservoir simulation
Reservoir simulation is an area of reservoir engineering in which computer models are used to predict the flow of fluids through porous media.-Uses:...
is the method used by the BOEMRE to calculate WCD as simulation can accurately model the rapid changes near well bore that occur in an uncontrolled blow out event. The BOEMRE currently uses the Merlin finite difference
Finite difference
A finite difference is a mathematical expression of the form f − f. If a finite difference is divided by b − a, one gets a difference quotient...
simulator and nodal analysis
Nodal analysis
In electric circuits analysis, nodal analysis, node-voltage analysis, or the branch current method is a method of determining the voltage between "nodes" in an electrical circuit in terms of the branch currents.In analyzing a circuit using Kirchhoff's circuit laws, one can either do nodal...
package to perform all WCD studies since using the software to determine the official flow rate for the Deepwater Horizon Oil Spill
Deepwater Horizon oil spill
The Deepwater Horizon oil spill is an oil spill in the Gulf of Mexico which flowed unabated for three months in 2010, and continues to leak fresh oil. It is the largest accidental marine oil spill in the history of the petroleum industry...
. Engineers typically use radial modeling to calculate WCD as a radial model can employ sufficiently small grid cell sizes around the well bore that increase in volume as cells extend into the aquifer
Aquifer
An aquifer is a wet underground layer of water-bearing permeable rock or unconsolidated materials from which groundwater can be usefully extracted using a water well. The study of water flow in aquifers and the characterization of aquifers is called hydrogeology...
.