Service: Measurement - Lost and Unaccounted For

Lost and Unaccounted For

• Assistance with determination and resolution of sources of lost and unaccounted for gas from the end devices to the measurement system. This includes assistance with audits of metering facilities and evaluation of gas sampling methodology and equipment.

• Ideally, there should be a balance between the gas going into a system (receipts), the gas already in the system (line pack), the gas used in the system and the gas going out of the system (deliveries) on at least a daily basis. Plus or minus balances that cannot be accounted for are called lost and unaccounted for gas.

• There can be many reasons for lost and unaccounted for gas in a system. Out of calibration transmitters, incorrect meter factors, low flow cutoffs, bogus measurement due to electrical interference or meter malfunction as well as incorrect gas analysis data can cause incorrect measurement. There can be numerical inaccuracies induced from conversion of the analog signal from the transducer to a digital signal in the flow computer or where ever the custody calculations are done. Numeric resolution (such as rounding errors or conversion to floating point numbers) can also be a problem as the data is moved from the site to the SCADA and/or metering system.

• Tools such as pipeline segmentation; inconsistencies between check measurement and custody measurement; or on-site and off-site measurement values can help pinpoint the location of problems. Once the probable location has been defined, detailed evaluations such as audits, comparison custody calculations with a third party software application, and evaluation of audit trail data can then be done. Detailed analysis usually leads to determination of the cause of the errors and development of a resolution strategy.

 

Services Offered:

Measurement
• Lost and Accounted For
• Instrumentation
• Gas Meters
• Meter Stations
• Integration

Automation and Control
• Control Strategies
• Flow Computers
• Communication

Additional Services
• White Papers