PR-015-12600-R01 Ability of Ultrasonic Meters to Measure Accurately in Compressor-Induced Pulsating Flows

Transmission and storage operations frequently move natural gas using reciprocating compressors that may generate flow pulsations. Most measurement systems cannot accurately measure the flow rate of a pulsating gas stream, and the resulting errors can cause inaccurate gas volumes and accounting imbalances. Recent advances in ultrasonic meters may provide the ability to function without measurement error in pulsating gas streams. Tests were performed to examine the relationship between ultrasonic meter transducer sampling rates, the frequency and amplitude of pulsations from reciprocating compressors, and meter accuracy as a possible basis for using ultrasonic meters in gas pipelines with varying pulsations. Two ultrasonic natural gas meters of current design were tested at SwRI in flows that simulated reciprocating compressor pulsations. Diagnostics and flow data were collected from the meters and analyzed to identify pulsation conditions in which the meters read accurately, or in which meter data could be used to correct measurement errors.