Engineering Design and Calibration of Gas Metering Systems in Era of Increasing Product Cost

Abstract

Abstract A new engineering design and calibration procedures for the natural gas metering system is presented that will enable the elimination of the over-sighted intrinsic errors in gas measurement, reduction to the barest minimum of the operational errors frequently incurred in the use of the flow meters, and resolution of the discrepancies between the various standards used in designing gas metering systems. As natural gas continues to gain prominence in the global energy mix and its price continues to appreciate, it becomes necessary (to take advantage of evolving technologies) to eliminate the systematic errors and minimize the random errors in gas measurement, the errors of which were hitherto considered insignificant in the face of calibration constraints. This paper explains why orifice flowmeters should now be calibrated online, emphasizes (using field and factory acceptance test (FAT) data) the need for online calibration of the new generation flowmeters even when equipped with self diagnostic mechanism, and presents the master prover selection procedure. The paper which is based on field experiences acquired over extended period of time during work visits to a number of gas fields in Nigeria, Europe and the United States of America, also reconciles the discrepancies existing between the two major standards (the AGA-3 and ISO 5167) used in the measurement of hydrocarbon gas.