1、Recommended Practice for Field Analysis of Crude Oil Samples Containing from Two to Fifty Percent Water by VolumeAPI RECOMMENDED PRACTICE 87FIRST EDITION, AUGUST 2007EFFECTIVE DATE: FEBRUARY 1, 2008REAFFIRMED, SEPTEMBER 2012Recommended Practice for Field Analysis of Crude Oil Samples Containing from
2、 Two to Fifty Percent Water by VolumeUpstream SegmentAPI RECOMMENDED PRACTICE 87FIRST EDITION, AUGUST 2007EFFECTIVE DATE: FEBRUARY 1, 2008REAFFIRMED, SEPTEMBER 2012Special NotesAPI publications necessarily address problems of a general nature. With respect to particular circumstances, local, state,
3、and federal laws and regulations should be reviewed.Neither API nor any of APIs employees, subcontractors, consultants, committees, or other assignees make any warranty or representation, either express or implied, with respect to the accuracy, completeness, or usefulness of the information containe
4、d herein, or assume any liability or responsibility 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 u
5、pon privately owned rights.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 public
6、ation and hereby expressly disclaims any liability 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 eng
7、ineering and operating practices. These publications are not intended to obviate the need for applying sound engineering judgment regarding when and where these publications should be utilized. The formulation and publication of API publications is not intended in any way to inhibit anyone from usin
8、g any other practices.Any manufacturer marking equipment or materials in conformance with the marking requirements of an API standard is solely responsible for complying with all the applicable requirements of that standard. API does not represent, warrant, or guarantee that such products do in fact
9、 conform to the applicable API standard.All rights reserved. No part of this work may be reproduced, 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, A
10、PI Publishing Services, 1220 L Street, N.W., Washington, D.C. 20005.Copyright 2007 American Petroleum InstituteForewordThis Recommended Practice is under the jurisdiction of the API Executive Committee on Drilling and Production Operations.Nothing contained in any API publication is to be construed
11、as granting any right, by implication or otherwise, for the manufacture, sale, or use of any method, apparatus, or product covered by letters patent. Neither should anything contained in the publication be construed as insuring anyone against liability for infringement of letters patent.This documen
12、t 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 of this publication or comments and questions concerning the procedures
13、 under which this publication was developed should be directed in writing to the Director of Standards, American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005. Requests for permission to reproduce or translate all or any part of the material published herein should also be address
14、ed 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 ascertained from the API Standards Department, telephone (202) 682-800
15、0. A catalog of API publications and materials is published annually and updated quarterly by API, 1220 L Street, N.W., Washington, D.C. 20005.Suggested revisions are invited and should be submitted to the Standards Department, API, 1220 L Street, NW, Washington, D.C. 20005, standardsapi.org.iiiCont
16、entsPageIntroduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
17、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.1 Normative . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
18、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.2 Informative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Terms and Definitions.
19、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Symbols and Abbreviated Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24.1 Symbols
20、and Nomenclature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24.2 Abbreviated Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
21、 . . . . 35 Sampling and Stream Mixing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35.1 Automatic Sampler and Stream Mixing Recommendations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45.
22、2 Sample Acquisition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Sample Handling and Mixing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
23、 . . . . . . . . . 66.1 Sample Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66.2 Laboratory Sample Mixing Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
24、. . . . . . . . . . . . . . . . . . 67 Test Apparatus Measurement Integrity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77.1 Glassware Verification Requirements. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25、 . . . . . . . . . . . . . . . . . . 77.2 Test Equipment Verification Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Analytical Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26、. . . . . . . . . . . . . . . . . . . . . . . . . . 88.1 Overview of Methods Considered . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88.2 Centrifuge Method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
27、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98.3 Graduated Cylinder Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118.4 Reduced Volume Distillation Method (Laboratory Referee Method) .
28、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Annex A Laboratory Testing Results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15Annex B Prior NEL Testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
29、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Figure1 Graduated Cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Tables1 Water Injection Testing Tolerances . . . . . . .
30、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52 Density Meter Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Weigh Scale Resolution . . . . . . .
31、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 Centrifuge Tube Calibration Table Example. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 Weigh Scale Devices. . . . . .
32、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166 Reference Oil Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 Gradu
33、ated Cylinder Method Results for Light Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178 Graduated Cylinder Method Results for Heavy Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 Centrifuge Method Resul
34、ts for Light Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1710 Centrifuge Method Results for Heavy Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1711 Distillation Method Res
35、ults for Light Oil. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1812 Distillation Method Results for Heavy Oil. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18vIntroduction This Recom
36、mended Practice addresses analytical methods for determining water content in crude oil streams for production allocation measurement applications, where the relative water fraction is higher than those normally encountered in custody transfer measurement applications. Generally, the measurements in
37、 these applications are made on the liquid outlet of two-phase (i.e. gas and liquid) separators. However, they may also be made on the oil outlet of three-phase (i.e. gas/oil/water) separators which also may experience high water contents in the oil outlet. In all cases the water content amounts enc
38、ountered are generally much higher than the water content amounts in custody transfer measurement situations.Other than the API Manual of Petroleum Measurement Standards (MPMS), Chapter 20.1, measurement standards have focused on sampling and analysis for custody transfer applications with relativel
39、y low water content (0 % to 2 % by volume). Likewise, ASTM sediment and water (S meaning absolute errorcP centipoisesft/s feet per secondg gramsmL milliliterm/s meter/secondpsi pounds per square inch (pressure)rel. relative; meaning relative errorRPM revolution per minuteS2) For most relevant applic
40、ations (i.e. separator liquid outflows) a static mixer will induce 5 % or less gas by volume in the stream. However, if it is known that more free gas will be present at the sample probe, this RP may not be applicable. Furthermore, no meter types currently in use for separator liquid outflow measure
41、ment are capable of tolerating large amounts of free gas (i.e. two-phase gas/liquid flow regimes). Gas breakout upstream of and at liquid meters is a significant contributor to measurement error. Therefore, the mixer and sampler should always be located downstream of the meter, but upstream of a bac
42、k-pressure control valve. This configuration minimizes metering errors while achieving near single-phase liquid conditions at the sample extraction point.5.2 Sample Acquisition5.2.1 Sample Acquisition from Automatic Sampler SystemsEach aliquot should only be taken directly into the laboratory glassw
43、are for analysis while circulating within the sample container mixing system. Sample container mixing systems can over-mix the oil/water mixture resulting in a tight oil/water emulsion. Therefore, tests should be conducted to determine optimal mixing times for analysis. 5.2.2 Acquiring Spot Samples
44、Spot sampling for water content is typically employed for well test applications and may be used in other allocation measurement situations. When taking spot samples and especially for well tests, there should be a sufficient number of representative samples taken for average water content to be det
45、ermined. For well tests it is preferable to take samples every two (2) hours or frequently enough to represent the flows over any cyclical flow pattern. Non-representative samples should not be used in determining average water fraction. Spot samples taken downstream of a separator dump valve where
46、the water fraction may vary from 100 % water to 100 % crude may seriously bias results. Similarly, for high water content streams, changes between the oil-continuous and water continuous phase may bias results. Spot samples should be taken only after adequately purging the sample probe and any attac
47、hed sample line.5.2.3 Spot Sample Extraction ApparatusIt is primarily recommended that the sample probe location within the pipe cross-section and the inlet configuration be in accordance the provisions of API MPMS Chapter 8.2. Furthermore, due to the high level of water content and the Table 1Water
48、 Injection Testing TolerancesWater Content Tolerance abs.2 % 0.1 %10 % 0.5 %20 % 1.0 %50 % 2.5 %6 API RECOMMENDED PRACTICE 87gravitational effects which cause in-pipe separation, it is recommended that the probe be located in vertical pipe section within two or three pipe diameters downstream of a s
49、tatic mixer. Alternatively, for spot sampling locations in horizontal pipes or where no specific mixing elements are used, it is recommended that these locations be confirmed as providing adequate results during the water injection tests as described in 5.1.1. As an exception to the provisions above, well test or other related spot samples taken directly from a test well riser or other piping located directly downstream of a choke are typically well mixed (without a mixer) and should also be representative, provided a probe is installed and that, in the case of a test separat
