Use the settings in this section to enable or disable flow conditions, and to adjust a condition's set point. Flow Conditions are used to determine when to open the sales valve and allow the well to flow. All enabled flow conditions must be accepted before the well is allowed to flow. Flow conditions are evaluated in the Wait For Flow state. When all enabled flow conditions are met the plunger control loop will move to the After Flow Delay state.
Each flow condition, except for the Minimum Off Time condition, has an associated configurable delay. This delay is implemented between the time that the condition is first met and then subsequently accepted. If the condition is no longer met during the delay period, the delay timer is reset and the program waits again for the condition to be met.
The delay is used to prevent a short term upset from making a condition appear as if it is met. The delay can be disabled by setting it to 0.
For example, if the value of Minimum Tubing Pressure is 500, and the Minimum Tubing Pressure Delay is 30, the actual tubing pressure must be less than the limit for 30 seconds before the condition is accepted.
Flow Conditions
After Shut In Delay
Specify a fixed delay between when the well is shut in and when flow conditions start being evaluated. This allows the well to settle before flow conditions are evaluated.
The Minimum Off Time condition sets a minimum amount of time for the well to be shut in. This condition has no delay, since it's already a delay. Timing starts from when the After Shut In delay expires.
The load ratio is 100 * (casing pressure - tubing pressure)/(casing pressure - line pressure) in percent. The lower the load ratio, the more energy is stored in the well. This condition is accepted when the calculated load ratio is less than the Maximum Load Ratio.
The User Flow Condition allows for custom user ladder logic to drive a flow condition. The condition is tied to a Modbus coil register that is specified in theInput/Output Modbus Registers Settings group that is used by the control loop. When the associated register is set to 1, the condition will be met. When the associated register is cleared, the condition will not be met.
Use this setting to select a set of optimization limits for this set of Flow Conditions. This setting has no effect if Enable Optimization is not enabled. See the Optimization sub section in the Operational Details section for information on how automatic optimization works.
Use this setting to configure the value of the Minimum Off Time condition when recovery mode is active. Recovery allows for an alternate setting of the Minimum Off Time condition when the number of consecutive plunger no arrivals exceeds a configured limit.
