Understand the Pressmon predicted pressure and flow rate calculations

The Pressure/Flow Rate Monitoring (Pressmon) application calculates the values of predicted pressure and/or flow rate points based upon the following formula, using a configured number of stored samples of telemetry data:

Where:

• P = Expected pressure.

• t = Time of expected pressure.

• b1 = Rate of Change (ROC) of pressure since the last sample (this is based on the least square method).

• b0 = The pressure at the start of the last time segment, based on the sum of all the samples (refer to the equation below).

  

  

Where:

• n = The number of sample points.

The formula is the same for flow rate, except that flow rate values are substituted for pressure values.

The Pressmon application compares the predicted value against the actual telemetered value. If the difference is greater than the first deadband, the application checks if the value violates the second deadband. If the second deadband is violated, the application issues alarms and events. The alarm message is based upon the four possible alarm states:

• Normal

• Pressure

• Pressure and Flow

• Flow