Uncertainty calculations for a crude oil metering system including bidirectional pipe prover, automatic sampling system and water draw; North Yaran Oil Field case study

The present study covers the methodology and case study of uncertainty calculations for the crude oil metering system of North Yaran Oil Field as one of the reference projects of Faramowj Pooya Co. consisting of a metering skid and a bidirectional pipe prover. The presented procedure for uncertainty estimation hires the ISO GUM. The calculation formulas are given, uncertainty of elements involved in metrology are calculated in detail for flow, temperature, pressure and density measurements; then, system total uncertainty is reported which lies in API-MPMS standard allowable limitations.Results reveal that combined uncertainty of temperature transmitter, pressure transmitter and density meter are ۰.۶۶oC, ۰.۰۳۳ bar and ۱.۴۸۳ kg/m۳, and the relative expanded uncertainty with ۹۵% confidence level, i.e., coverage factor of ۲, is ۰.۱۶۵۴% for the K-factor and ۱۱.۸۶۸۷۶ Sm۳/hr. (۰.۲۱۹۸%) for the standard measured volumetric flow rate which is in allowable range defined by API MPMS standard (۰.۲۵%).

Keywords:

Uncertainty , Fiscal measurement , Metering system , Crude oil , Flow rate , Density meter