1、Recommended Practice for Gas Lift System Design and Performance PredictionAPI RECOMMENDED PRACTICE 11V8FIRST EDITION, SEPTEMBER 2003REAFFIRMED, MARCH 2015Recommended Practice for Gas Lift System Design and Performance PredictionUpstream SegmentAPI RECOMMENDED PRACTICE 111V8FIRST EDITION, SEPTEMBER 2
2、003REAFFIRMED, MARCH 2015SPECIAL NOTESAPI publications necessarily address problems of a general nature. With respect to partic-ular circumstances, local, state, and federal laws and regulations should be reviewed.API is not undertaking to meet the duties of employers, manufacturers, or suppliers to
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4、 and conditions should be obtained from the employer, the manufacturer orsupplier of that material, or the material safety data sheet.Nothing contained in any API publication is to be construed as granting any right, byimplication or otherwise, for the manufacture, sale, or use of any method, appara
5、tus, or prod-uct covered by letters patent. Neither should anything contained in the publication be con-strued as insuring anyone against liability for infringement of letters patent.Generally, API standards are reviewed and revised, reaffirmed, or withdrawn at least everyfive years. Sometimes a one
6、-time extension of up to two years will be added to this reviewcycle. This publication will no longer be in effect five years after its publication date as anoperative API standard or, where an extension has been granted, upon republication. Statusof the publication can be ascertained from the API S
7、tandards department telephone (202)682-8000. A catalog of API publications, programs and services is published annually andupdated biannually by API, and available through Global Engineering Documents, 15 Inv-erness Way East, M/S C303B, Englewood, CO 80112-5776. This document was produced under API
8、standardization procedures that ensure appropri-ate notification and participation in the developmental process and is designated as an APIstandard. Questions concerning the interpretation of the content of this standard or com-ments and questions concerning the procedures under which this standard
9、was developedshould be directed in writing to the Director of the Standards department, American Petro-leum Institute, 1220 L Street, N.W., Washington, D.C. 20005. Requests for permission toreproduce or translate all or any part of the material published herein should be addressed tothe Director, Bu
10、siness Services.API standards are published to facilitate the broad availability of proven, sound engineer-ing and operating practices. These standards are not intended to obviate the need for apply-ing sound engineering judgment regarding when and where these standards should beutilized. The formul
11、ation and publication of API standards is not intended in any way toinhibit anyone from using any other practices.Any manufacturer marking equipment or materials in conformance with the markingrequirements of an API standard is solely responsible for complying with all the applicablerequirements of
12、that standard. API does not represent, warrant, or guarantee that such prod-ucts do in fact 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,
13、or otherwise, without prior written permission from the publisher. Contact the Publisher, API Publishing Services, 1220 L Street, N.W., Washington, D.C. 20005.Copyright 2003 American Petroleum InstituteFOREWORDThis Recommended Practice (RP) is under the jurisdiction of the API Committee on Stan-dard
14、ization of Production Equipment (Committee 11).This document presents RPs for the design of gas lift systems. Other API Specifications,API RPs, and Gas Processors Suppliers Association (GPSA) documents are referenced andshould be used for assistance in design and operation.Introduction to Gas Lift S
15、ystem Design and Performance Prediction API RP 11V8 Recommended Practice for Gas Lift System Design and Performance Pre-diction, provides two functions:A broad overview of gas lift systems and various major types of gas lift operations. Recommended practices for gas lift system design and for modeli
16、ng methods used inperformance prediction. All key system components are reviewed to provide guidancefor engineers, technicians, well analysts, and operating personnel who are involved ingas lift system analysis, troubleshooting, design, and optimization. The primary purpose of this API Recommended P
17、ractice (RP) is to emphasize gas lift as asystem and to discuss methods used to predict its performance. Information must be gath-ered and models validated prior to a system design, which must precede wellbore gas liftmandrel and valve design. The subsurface and surface components of the system must
18、 bedesigned together to enhance the strengths of each and to minimize the constraints. This recommended practice bridges and enhances the general information from the APIGas Lift Manual(Book 6 of the Vocational Training Series) and the technical details of otherAPI Gas Lift RPs, each of which contai
19、n information on a specific subject or part of theoverall gas lift system. The gas lift system designer or operator should have and becomefamiliar with the full set of documents from the API (American Petroleum Institute), GPSA(Gas Processors Suppliers Association), and ISO (International Standards
20、Organization) thatrelate to gas lift system components:APIGas Lift Manual(Book 6 of the Vocational Training Series)API Spec 11V1Gas Lift EquipmentAPI RP 11V2Gas Lift Valve Performance Testing API RP 11V5Operation, Maintenance, and Troubleshooting Gas Lift InstallationsAPI RP 11V6Design of Continuous
21、 Flow Gas Lift InstallationsAPI RP 11V7Repair, Testing, and Setting Gas Lift ValvesAPI Spec 12GDUGlycol-Type Gas Dehydration UnitsAPI Spec 12JOil and Gas SeparatorsAPI Std 617Centrifugal Compressors for General Refinery ServiceAPI Std 618Reciprocating Compressors for General Refinery ServiceAPI Manu
22、al of Petroleum Measurement Standards (MPMS)Chapter 5, Metering;Chapter 14, Natural Gas Fluids MeasurementGPSAEngineering Data Book ISO 17078Gas Lift Equipment SpecificationsiiiivAPI publications may be used by anyone desiring to do so. Every effort has been made bythe Institute to assure the accura
23、cy and reliability of the data contained in them; however, theInstitute makes no representation, warranty, or guarantee in connection with this publicationand hereby expressly disclaims any liability or responsibility for loss or damage resultingfrom its use or for the violation of any federal, stat
24、e, or municipal regulation with which thispublication may conflict.Suggested revisions are invited and should be submitted to API, Standards department,1220 L Street, NW, Washington, DC 20005.CONTENTSPage1 OVERVIEW OF A GAS LIFT SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
25、. . . 11.1 Major Components of a Gas Lift System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Ways in Which System Components Interact . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 TYPES OF GAS LIFT SYSTEMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26、 . . . . . . . . . . . 42.1 Continuous Gas Lift. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52.2 Intermittent Gas Lift . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62.3 Gas Lift with Plunger. . . . .
27、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82.4 Gas Lift Tubing/Packer Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 INFORMATION REQUIRED FOR EFFECTIVE GAS LIFT . . . . . . . . . . . . . . . . . . . 93.1 Fluid PVT Data
28、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103.2 Flowing Pressure and Temperature Surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123.3 Production Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
29、 . . . . . . . . . . . . 143.4 Gas Lift Valve Performance Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163.5 Field Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184WELL DELIVERABILITY . . . . . . . . . . . . .
30、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 224.1 Basic Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 234.2 System Models. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
31、 . . . . 295 FACTORS WHICH AFFECT POTENTIAL PRODUCTION RATE AND GAS INJECTION REQUIREMENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345.1 Casing Pressure and Gas Injection Rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345.2 Depth of Inj
32、ection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 345.3 Casing, Tubing, and Flowline Sizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 365.4 Gas Lift Valves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
33、 . . . . . . . . . . . . . . . . . 385.5 Reservoir Depth, Pressure, and Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . 395.6 Well Inflow Productivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395.7 Percent Water in Produced Fluid . . . .
34、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405.8 Solution and Free Gas In Produced Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 405.9 Operating Separator Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 415.10 Wellbor
35、e Deviation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 416 OTHER GAS LIFT DESIGN CONSIDERATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . 426.1 Gas Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
36、 . . . . . . . . . . . 426.2 Gas Lift Gas Distribution System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 516.3 Injection Gas Measurement and Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 526.4 Gathering, Testing, and Handling of Produced Fluids . .
37、 . . . . . . . . . . . . . . . . . . 556.5 Special Design Cases. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 567 GAS LIFT OPTIMIZATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 577.1 Economic Basis for Optimi
38、zation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 587.2 Determination of Gas Lift System Economic Costs and Benefits . . . . . . . . . . . 587.3 Implementation of Field Optimization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 597.4 What is Practical a
39、nd What is Impractical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63vPage8 COMPUTER DESIGN TOOLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 638.1 Vertical Pressure Profile Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
40、 . . . . 648.2 Vertical Temperature Profile Models. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 668.3 Well Inflow Performance Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 679 OPERATING CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . .
41、. . . . . . . . . . . . . . . . 699.1 Gas Lift Operators Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 699.2 Design Strategies for Effective Long-term Operation . . . . . . . . . . . . . . . . . . . . 719.3 Check List of Gas Lift Problems and Recommendations.
42、 . . . . . . . . . . . . . . . . . 73Figures1-1 Gas Lift System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-2 Gas Lift Valves and Mandrels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21-3 Injection Press
43、ure Operated (IPO) Gas Lift Valve . . . . . . . . . . . . . . . . . . . . . . . . 32-1 Flowing and Static Gas Lift Gradients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52-2 Intermittent Lift Cycle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
44、 . . . . . 62-3 Two-packer Chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72-4 Insert Chamber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72-5 Gas Lift with Plunger . . . . . . . . . . . .
45、. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82-6 Open Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92-7 Semi-closed Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
46、 . . . . 93-1 High, Low, and Correct Calculated Gradients Obtained by Adjusting Fluid Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123-2 IPO and PPO Valves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
47、. . . . . . . 173-3 Wellhead Pressure Delivery Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203-4 Production Delivery vs. Injection Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214-1 Produced Fluid and Injection Gas Pressure Gradients . . . . .
48、. . . . . . . . . . . . . . . 244-2 Gas Lift Deliverability Curve Showing Measured Tests . . . . . . . . . . . . . . . . . . 254-3 Temperature Gradients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 274-4 Reservoir Inflow Performance (PI) . . . . . . . . . .
49、 . . . . . . . . . . . . . . . . . . . . . . . . . 284-5 InflowOutflow Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294-6 InflowOutflow Performance with Natural Flow and Gas Lift . . . . . . . . . . . . . 304-7 Equilibrium Curve for Low PI Well . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314-8 Equilibrium Curve for High PI Well Showing Unloading Rates . . . . . . . . . . . . 314-9 Production and Gas Injection Tests Identify Under-performing Wells . . . . . . . 334-10 Wellhead Delivery Curves and the Flowline
