API MPMS 12.2.1:1995(R2014) pdf download.Manual of Petroleum Measurement Standards Chapter 12—Calculation of Petroleum Quantities
1.1 Purpose
When most of the older standards were written, mechan- ical desk calculators were widely used for calculating measurement documentation, and tabulated values were used more widely than is the case today. Rules for rounding and the choice of how many figures to enter in each calcula- tion step were often made on the spot. As a result, different operators obtained different results from the same data. This five-part publication consolidates and standardizes calculations pertaining to metering petroleum liquids using turbine or displacement meters and clarifies terms and expressions by eliminating local variations of such terms. The purpose of standardizing calculations is to produce the same unbiased answer from the given data. So that different operators can obtain identical results from the same data, the rules for sequence, rounding, and discrimination of figures (or decimal places) have been defined.
1.2 Scope
This document provides standardized calculation methods for the quantification of liquids and the determination of base prover volumes under defined conditions, regardless of the point of origin or destination or the units of measure required by governmental customs or statute. The criteria contained in this document allow different entities using various computer languages on different computer hardware (or manual calculations) to arrive at identical results using the same standardized input data. The publication rigorously specifies the equations for computing correction factors, rules for rounding, calcula- tional sequence, and discrimination levels to be employed in the calculations. No deviations from these specifications are permitted since the intent of this document is to serve as a rigorous standard.
1.3.1 PART 1—INTRODUCTION
The base (reference or standard) volumetric determination of metered quantities is discussed along with the general terms required for solution of the various equations. General rules for rounding of numbers, including field data, intermediate calculational numbers, and discrimination levels, are specified within the context of this standard. For the proper use of this standard, a discussion is presented on the prediction of the liquid’s density at flowing and base conditions. An explanation of the principal correction factors associ- ated with dynamic measurement are presented in a clear, concise manner.
1.3.3 PART 3—PROVING REPORTS
The application of this standard to the calculation of proving reports is presented for base volumetric calculations in conformance with North American industry practices. Proving reports are utilized to calculate the following meter correction and performance indicators: meter factors (MF), composite meter factors (CMF), K-factors (KF), composite K- factors (CKF), and meter accuracy factor (MA). The determi- nation of the appropriate term is based on both the hardware and the user’s preference.