Investigation of Metering Station Calibration Practices for Fiscal Gas Measurement in Sokoto State

Fiscal gas metering accuracy is fundamental to the equitable commercial settlement of gas transactions between producers, transporters, and consumers. This study investigates the calibration practices and accuracy verification procedures at fiscal gas metering stations in Sokoto State, focusing on metering points supplying the Sokoto Rima Industrial Park and two fertiliser-related facilities. The research employs a compliance assessment methodology, reviewing calibration certificates, test records, and maintenance logs for the installed fiscal metering systems, and comparing practices against ISO 17089 and the NMDPRA fiscal metering regulations. The study conducts calibration verification tests using a portable transfer standard meter transported from the National Metrology Institute of Nigeria (NMIN). Calibration parameters assessed include meter factor accuracy, pressure transducer calibration status, temperature transmitter drift, and gas chromatograph calibration certificate validity. Findings reveal that fiscal meters at two of the three studied stations are operating beyond their mandatory 12-month calibration interval without renewal certification, and that several pressure transmitters exhibit biases exceeding the allowable error band. The study estimates the financial implications of these calibration deficiencies for both gas supplier and consumer in the studied transactions. Recommendations include mandatory electronic calibration management systems, increased NMDPRA compliance inspection frequency, and investment in portable transfer standard meter infrastructure for northern Nigerian metering audits. Keywords: fiscal metering, calibration, gas measurement, Sokoto, metering accuracy.