1、Manual of Petroleum Measurement Standards Chapter 13.3 Measurement Uncertainty SECOND EDITION, DECEMBER 2017Special Notes API publications necessarily address pr oblems of a general nature. With respect to particular circumstances, local, state, and federal laws and regulations should be reviewed. N
2、either API nor any of APIs employ ees, subcontractors, consultants, co mmittees, or other assignees make any warranty or representation, either express or implied, with respect to the accu racy, completeness, or usefulness of the information contained herein, or assume any liability or responsibilit
3、y for any use, or the results of such use, of any information or process disclosed in this publication. Neither API nor any of APIs employees, subcontractors, consultants, or other assignees represent that use of this publication would not infringe upon privately owned rights. API publications may b
4、e used by anyone desiring to do so. Every effort has been made by the Institute to ensure the accuracy and reliability of the data c ontained in them; however, the Institute makes no representation, warranty, or guarantee in connection with this publicat ion and hereby expressly di sclaims any liabi
5、lity or responsibility for loss or damage resulting from its use or for the violation of any authorities having jurisdiction with which this publication may conflict. API publications are published to facilitate the broad availability of proven, sound engineering and operating practices. These publi
6、cations are not intended to obviate the need for applying sound engineering judgment regarding when and where these publications should be utili zed. The formulation and publication of API publications is not intended in any way to inhibit anyone from using any other practices. Any manufacturer mark
7、ing equipment or materials in conformance with the marking requirements of an API standard is solely responsible for complying with all the applic able requirements of that st andard. API does not represent, warrant, or guarantee that such products do in fact conform to the applicable API standard.
8、All rights reserved. No part of this work may be reproduced, translated, stored in a retrieval system, or transmitted by any means, electronic, mechanical, photocopying, recording, or otherwise, without prior written permission from the publisher. Contact the Publisher, API Publishing Services, 1220
9、 L Street, NW, Washington, DC 20005. Copyright 2017 American Petroleum InstituteForeword Nothing contained in any API publication is to be construed as granting any right , by implication or otherwise, for the manufacture, sale, or use of any met hod, apparatus, or product covered by letters patent.
10、 Neither should anything contained in the publication be construed as insuring anyone against liability for infringement of letters patent. The verbal forms used to express the provisions in this document are as follows. Shall: As used in a standard, “shall” denotes a minimum requirement in order to
11、 conform to the standard. Should: As used in a standard, “should” denotes a recommendation or that which is advised but not required in order to conform to the standard. May: As used in a standard, “may” denotes a course of action permissible within the limits of a standard. Can: As used in a standa
12、rd, “can” denotes a statement of possibility or capability. This document was produced under API standardization procedures that ensure appropriate notification and participation in the developmental process and is designated as an API standard. Questions concerning the interpretation of the content
13、 of this publication or comments and questions concerning the procedures under which this publication was developed should be directed in writing to the Di rector of Standards, American Petroleum Institute, 1220 L Street, NW, Washington, DC 20005. Requests for permission to r eproduce or translate a
14、ll or any part of the material published herein should also be addressed to the director. Generally, API standards are reviewed and revised, reaffirmed, or withdrawn at least every five years. A one-time extension of up to two years may be added to this review cycle. Status of the publication can be
15、 ascertained from the API Standards Department, telephone (202) 682-8000. A cata log of API publications and materials is published annually by API, 1220 L Street, NW, Washington, DC 20005. Suggested revisions are invited and s hould be submitted to the Standards Department, API, 1220 L Street, NW,
16、Washington, DC 20005, standardsapi.org. iiiContents Page 1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2 Normative References . . . . . . . . . . . . . . . . . . . . . . . . .
17、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 3 Terms, Definitions, Acronyms, Abbreviations, and Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3.1 Terms and Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3.2 Acronyms, Abbreviations, and Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 4 Basic Concepts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.2 Measurement Method. . . . . . . . . . . . . .
20、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.3 True Quantity Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.4 Error . . . . . . . . . .
21、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.5 Statistical Basis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
22、 . . . 10 4.6 Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.7 Confidence Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23、. . . . . . . . . . . . . . . . . . 11 4.8 Type A vs Type B Uncertainties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.9 Representative Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
24、 . . . . . . . . . . . . . . . . . . . . . . 11 4.10 Mean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.11 Standard Deviation . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 4.12 Standard Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 4.13 Degrees of Freedom . . . . . . . . . . . . . . . .
26、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 4.14 Determining Confidence Interval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 4.15 Correlation Coefficient . . . . . . .
27、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 4.16 Independent and Dependent Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.17 Combining Uncertainties . . .
28、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.18 Probability Distributions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 5 Evaluating Unc
29、ertainty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 5.1 General. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
30、. . . . 20 5.2 Determine the Measurement Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 5.3 Record Elemental Error Sources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31、 . . 21 5.4 Create a Primary Uncertainty Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 5.5 Classify and Evaluate Uncertainty Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 5.6
32、Determine Sensitivity Coefficients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5.7 Determine Correlation Coefficients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 5.
33、8 Determine Combined Standard Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 5.9 Determine Expanded Uncertainty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 5.10 Reporti
34、ng Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Annex A (informative) Monte Carlo Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
35、33 Annex B (informative) Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Annex C (normative) Formal Proof of Equation (7a) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
36、 . . . 54 Annex D (informative) Report Significant Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Annex E (normative) Using a Simplified Estimate of Standard Deviation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Annex F
37、(informative) Dixons Q-Test for Outliers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
38、 . . . . . . . 65 vContents Page Figures 1 Accuracy/Precision Comparisons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2 Normal Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
39、 . . . . . . . . . . . . . . . . . . . . . 18 3 Triangular Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 4 Rectangular Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
40、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5 Relationship between Measurement Model and Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 6 Relationship between the Uncertainty of the Measurement Model and the Uncertainty of the Inputs. . . . . .
41、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 7 Hierarchal Relationship of all Uncertainty Components of a Measurement Model . . . . . . . . . . . . . . . 22 B.1 Vector c, Matrix Diag(c) and Vector u using
42、Data from Example B1 . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 B.2 Matrix R using Data from Example B1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 B.3 Result of Multiplying Diag(c) and u from Figure B.1 Diag(c) u. . . . .
43、. . . . . . . . . . . . . . . . . . . . . . . . . . 44 B.4 Result of Transposing Figure B.3 Diag(c) uT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 B.5 Result of Multiplying Figure B.4 by Matrix R Found in Figure B.1 Diag(c) uT R . . . . . . . . . . . . .
44、 44 B.6 Result of Multiplying the Matrix in Figure B.5 by the Matrix in Figure B.3 . . . . . . . . . . . . . . . . . . . . . . 44 B.7 The Matrices Associated with Diag(c) uT RT and Diag(Diag(c) uT RT) . . . . . . . . . . . . . . 45 B.8 The Relative Contribution of Each Component . . . . . . . . . .
45、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 D.1 Uncertainty of the Transmitter Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 D.2 Uncertainty of the Transmitter after Adjustment. . . . . . . . . . . . . . . .
46、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58 Tables 1 Data with Same Mean but Different SDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2 Student t Factors for Individual Measurements at Various Confidence Levels . . . . . . .
47、 . . . . . . . . . . . 14 3 Example of a Primary Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 4 Matrix 1Universe of Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
48、. . . . . . . . . . 30 5 Matrix 2Correlation Matrix (Informative). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 B.1 Example Conditions and Correction Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
49、. . 35 B.2 Primary Uncertainty Table for Meter Factor Example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 B.3 Classification and Evaluation of Uncertainty Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 B.4 Sensitivity of Uncertainty Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 B.5 Correlation Matrix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .