Manual of Petroleum Measurement Standards

Chapter 12—Calculation of Petroleum

Quantities

Section 2—Calculation of Petroleum Quantities Using Dynamic Measurement Methods and Volumetric Correction Factors

Part 2—Measurement Tickets

THIRD EDITION, JUNE 2003

REAFFIRMED, FEBRUARY 2016

Manual of Petroleum Measurement Standards

Chapter 12—Calculation of Petroleum

Quantities

Section 2—Calculation of Petroleum Quantities Using Dynamic Measurement Methods and Volumetric Correction Factors

Part 2—Measurement Tickets

Measurement Coordination

THIRD EDITION, JUNE 2003 REAFFIRMED, FEBRUARY 2016

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Copyright ? 2003 American Petroleum Institute

FOREWORD

This ?ve-part publication consolidates and presents standard calculations for metering petroleum liquids using turbine or displacement meters. Units of measure in this publication are in International System (SI) and United States Customary (USC) units consistent with North American industry practices.

This standard has been developed through the cooperative efforts of many individuals from industry under the sponsorship of the American Petroleum Institute and the Gas Pro- cessors Association.

API publications may be used by anyone desiring to do so. Every effort has been made by the Institute to assure the accuracy and reliability of the data contained in them; however, the Institute makes no representation, warranty, or guarantee in connection with this publication and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any federal, state, or municipal regulation with which this publication may con?ict.

Suggested revisions are invited and should be submitted to the standardization manager, American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005.

iii

Page

Figures

1 Measurement Ticket Flow Chart 8

Tables

1. Speci?ed Discrimination Levels for Field Data 9

2. Liquid Density Discrimination Levels 9

3. Temperature Discrimination Levels 9

4. Pressure Discrimination Levels 9

5. Compressibility Factor Discrimination Levels 9

7 Volume Discrimination Levels 10

6 Correction Factor Discrimination Levels 10

Chapter 12—Calculation of Petroleum Quantities

Section 2—Calculation of Petroleum Quantities Using Dynamic Measurement Methods and Volumetric Correction Factors

Part 2—Measurement Tickets

1. Purpose

   When most of the older standards were written, mechani- cal desk calculators were widely used for calculating mea- surement documentation, and tabulated values were used more widely than is the case today. Rules for rounding and the choice of how many ?gures to enter in each calculation step were often made on the spot. As a result, different opera- tors obtained different results from the same data.

   This ?ve-part publication consolidates and standardizes calculations pertaining to metering petroleum liquids using turbine or displacement meters and clari?es 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 opera- tors can obtain identical results from the same data, the rules for sequence, rounding, and discrimination of ?gures (or dec- imal places) have been de?ned.

   
   

2. Scope

   This document provides standardized calculation methods for the quanti?cation of liquids and the determination of base prover volumes under de?ned 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 calcu- lations) to arrive at identical results using the same standard- ized input data.

   The publication rigorously speci?es the equations for com- puting correction factors, rules for rounding, calculational sequence, and discrimination levels to be employed in the cal- culations. No deviations from these speci?cations are permit- ted since the intent of this document is to serve as a rigorous standard.

   
   

3. Application of Part 2

   The purpose of standardizing the terms and arithmetical procedures employed in calculating the amount of petro- leum liquid on a measurement ticket is to avoid disagree- ment between the parties involved. The purpose of Part 2,

   ?Measurement Tickets,? is to obtain the same unbiased answer from the same measurement data, regardless of who or what does the computing.

   1

   Calculations of correction factors and volumes may be done using continuous online integration techniques if agreed between the parties. The results of these calculations may not agree with the methods contained in this standard due to the variability in obtaining ?owing parameters. However, the equations for computing correction factors and the rules for rounding, calculation sequence, and discrimination levels for any continuous online integration methods shall be identical to the speci?cations contained in this standard.

   A measurement ticket is a written acknowledgment of a transfer of petroleum liquids and is the legal document of transfer. In addition, it serves as an agreement between the authorized representatives of the parties concerned as to the measured quantities and quality of the liquid. The measure- ment ticket shall contain all ?eld data required to calculate the metered quantities.

   Care must be taken to ensure that all copies of a measure- ment ticket are legible. Proper ?scal procedures forbid mak- ing corrections or erasures on a measurement ticket unless the interested parties agree to do so and initial the ticket to that effect. Should a mistake be made, the ticket should be marked

   ?VOID? and a new ticket prepared. The voided ticket should be attached to the new one to support the validity of the cor- rected ticket.

   
   

4. Organization of Standard

The standard is organized into ?ve separate parts. Part 1 contains a general introduction for dynamic calculations. Part 2 focuses on the calculation of metered quantities for ?s- cal purposes or measurement tickets. Part 3 applies to meter proving calculations for ?eld operations or proving reports. Parts 4 and 5 apply to the determination of base prover vol- umes (BPVs).

4.1 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 equations.

General rules for rounding of numbers, including ?eld data, intermediate calculational numbers, and discrimination levels, are speci?ed.

For the proper use of this standard, prediction of the density of the liquid in both ?owing and base conditions is discussed.