Excess Policy Tab

The Excess Policy tab is the area where you can are schedule the actions to be taken should a facility reaches a state of excess or threatened excess.

An excess state is defined as the moment when the facility's potential production is above its actual production; by "potential production" it is understood the amount of fluid that can be delivered by wells directly or indirectly connected to the facility at a given moment.

A threatened excess state is defined as the moment when the facility's unused capacity is below a given threshold; in other words, a threatened excess state occurs when a capacity is apparently about to be exceeded.

The possible causes for a facility's actual production to be lower than its potential are:

The capacity of any of its out connectors is exceeded by the potential production; see Connectors and Connections and Capacity Sub-Tab.
Its potential production surpasses the Deliverability defined for the current period.
There is a downtime defined for the facility; see Facility Operation Options and Downtime Simulation.
The capacity, deliverability or downtime definition of any other facility located downstream from it indirectly curtail the actual production of the facility. Notice that this means that a facility's excess policy may end up being triggered by definitions that are external to it.

There are four different actions that can be taken to resolve a (threatened) excess situation:

Add Expansion: Expand one or more of the facility's capacities. Triggered by a threatened excess state.
Add Shut In: Temporarily or permanently shut in wells feeding this facility. Triggered by an excess state.
Add Defer Drilling: Defer drilling wells that feed this facility. Triggered by an excess state.
Add Cloning: Build a replica of this facility. Triggered by a threatened excess state.

If no actions are taken, or if after applying the selected actions the potential production is still above the actual production, fluids will simply be scaled back according to the defined choking settings. See Well Chokes below.

Each policy will be represented by a separate pane. Use the Activecheck box to activate/deactivate existing excess policies, and the Delete button to delete them permanently.

Priority between facilities is defined by order of precedence in the routing: excess policies are always checked and honored in upstream facilities before proceeding downstream.

If more than one excess policy is defined for the same facility, the following should be taken into account:

Expansions are applied consecutively, in the order they were defined and are presented in the tab. Each new expansion is not evaluated nor performed until the previous one has been completed.

Facility cloning policies are applied simultaneously. It is not advisable to define more than one cloning policy for the same facility.
Multiple shut in policies are resolved consecutively during the same step. Only if the first policy has not removed the excess state is the second one evaluated, and so on.
Multiple defer drilling policies are evaluated simultaneously and independently from each other.
It is possible to define different types of excess policies for the same facility, and they do not conflict with each other. However, it is not advisable to use expansion and cloning policies simultaneously, since they follow a different logic and are not intended to be used concurrently. For example, if a facility is first expanded by a policy and then cloned, the cloned facility will be identical to the original facility without the expansion and will inherit the policy, i.e., will be expanded should another excess state occur.

When an Expansion is created, the expansion connectors start with the same capacity as the ones already defined for the facility connectors. If instead you add connectors to a facility that already has an expansion, the expansion connectors will start with the default value (0).

Note also that constraints on injection are addressed differently. SeeInjection Facilities and How is water and gas injection constrained?