1、API BULL*bJ 92 O732290 OSOOOOL 9 Bulletin on Testing of Oilfield Elastomers - A Tutorial API BULLETIN 6J (BUL 6J) FIRST EDITION, FEBRUARY 1, 1992 American Petroleum Institute 1220 L Street, Northwest 11 Washington, DC 20005 - API BULL*bJ 92 0732290 0500002 O Issued by AMERICAN PETROLEUM INSTITUTE Pr
2、oduction Department FOR INFORMATION CONCERNING TECHNICAL CONTENTS OF THIS PUBLICATION CONTACT THE API PRODUCTION DEPARTMENT, SEE BACK COVER FOR INFORMATION CONCERNING HOW TO OBTAIN ADDITIONAL COPIES OF THIS PUBLICATION. 1201 MAIN STREET, SUITE 2535, DALLAS, TX 75202-3904 - (214) 748-3841. Users of t
3、his publication should become familiar with its scope and content, including any provisions it may have regarding marking of manufactured products. This publication is intended to supplement rather than replace individual engineering judgment. OFFICIAL PUBLICATION REG. U.S. PATENT OFFICE Copyright Q
4、 1992 American Petroleum Institute API BULL*bJ 92 O732290 0500003 2 NOTE: This is a first edition of this bulletin and was authorized by letter ballot by the Committee on Standard- ization of Valves and Wellhead Euuimnent . 2 American Petroleum Institute Requests for pemission to reproduce m transla
5、te all m any part of the material published herein should be addressed to the Director. Production Department. TABLE OF CONTENTS Page POLICY 3 FOREWORD . 4 SECTION 1: SCOPE 4 SECTION 2: DISCLAIMER . 4 SECTION 3: REFERENCES . 4 SECTION 4: ENVIRONMENT 6 SECTION 5: TESTING OPTIONS FOR EVALUATION . 8 SE
6、CTION 6: GUIDELINES FOR EVALUATION OF TEST RESULTS 10 SECTION 7: ENVIRONMENTAL SIMULTATION 11 SECTION 8: OTHER CONSIDERATIONS 13 SECTION 9: SUMMARY . 15 e I Ameriean Petroleum Institute. 1201 Main Street. Suite 2535. Dallas TX 75202.8904 . API BULLxbJ 92 0732290 0500004 4 Bu1 6J: Testing of Oilfield
7、 Elastomers -A Tutorial 3 O POLICY API PUBLICATIONS NECESSARILY ADDRESS PROBLEMS OF A GENERAL NATURE. WITH RESPECT TO PARTICULAR CIRCUMSTANCES, ULATIONS SHOULD BE REVIEWED. API IS NOT UNDERTAKING TO MEET DUTIES PLIERS TO WARN AND PROPERLY TRAIN AND POSED, CONCERNING HEALTH AND SAFETY RISKS AND PRECA
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12、troleum Institute FOREWORD American Petroleum Institute (API) Bulletins are pub- lished to provide information for which there is a broad industry need but which does not constitute either Specifications or Recommended Practices. Any Bulletin may be used by anyone desiring to do so, and a diligent e
13、ffort has been made by API to assure the accuracy and reliability of the data contained SEC1 SCI 1.1 This document is a tutorial for the evaluation of elastomer test samples or actual elastomeric seal members intended for use in the oil and gas industry. In earlier times, most of the oil and gas pro
14、duction was from sweet, low pressure wells and oilfield equipment manufacturers could supply low durometer nitrile rub- ber for seal members and the customers could depend on the seal with reliability. With time, these oil reserves have been depleted and the search for oil and gas has led to the dev
15、elopment of deep, high pressure reservoirs and/or sour (H,S), corrosive oil resources. SEC1 DISCL 2.1 It is the intent of this document to outline several tests which can be conducted to attempt to predict the performance of elastomeric seal materials and members in related environments. It is not w
16、ithin the scope of this document to either offer any correlation between the data obtained from a screening test and the actual service performance of the seal member or to present any pass/fail criteria. SECT REFER 3.1 Terminology. The following terms, definitions, expressions, abbreviations, etc.,
17、 are commonly used in the oilfield seal technology and in this bulletin but also apply to the design of seals, elastomers, and pressure- holding devices in general. There is no attempt to give detailed explanations or derivation of the terms: instead herein. However, the Institute makes no represent
18、ation, warranty or guarantee in connection with the publica- tion of any bulletin and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use, for any violation of any federal, state, or municipal regulation with which an API recommenda- tion may conflict
19、, or for the infringement of any patent resulting from the use of this publication. ON 1 )PE In a prospective application, the customer and the oil- field equipment manufacturer may not really be sure of the performance of the seal materials and members in the equipment. Many tests exist which evalu
20、ate the performance of a seal material or member. It is the intent of this document to review testing criteria, environments, evaluation procedures, guidelines for comparisons, and effects of other considerations on the evaluation of elastomeric seal materials and members. ION2 LIMER In the oil and
21、gas industry the relationship between elastomer screening test conditions and actual service conditions is only approximate, at best. Consequently, the correlation between the results of any screening tests and actual service life or performance is also approximate. It has been shown that the gross
22、effects ,observed in the screening tests my identify possible problems in field applications. The extent of the corre- lation has not been recognized or quantified. ON 3 3NCES a concise description of the common terminology is given. Additional lists of terms can be found in other API or ASTM public
23、ations such as API Spec 6A or in “Glossary of Oilfield Production Terminology,” 1st ed., Jan. 1988, or ASTM DE66 in Volume 9.01 of the Cur- rent Annual Book of ASTM Standards. API BULL*bJ 92 0732290 050000b B Bu1 6J: Testing of Oilfield Elastomers -A Tutorial 6 ACS - American Chemical Society. AFLAS
24、 - See fluoroelastomer. ANTIEXTRUSION DEVICE - Plastic, metal, wire, etc., rings and packings used to block the extrusion of the elastomer seal. ASTM - American Society for Testing and Materials. BUNA-N - Trademark for acrylonitrile butadiene elastomer (NBR). Other trademark names are KRYNAC, HYCAR,
25、 PERBUNA, CHEMIGUM and PARACRIL. BUTTON - A cylindrical shaped, standardized size rubber specimen or pellet used for testing physical and chemical properties. COMPOUND - The thorough mixture of raw rubber or elastomer with other ingredients and additives which will allow the base material to be mold
26、ed and cured in order to optimize its physical, thermal, mechanical, and chemical resistance properties. COMPRESSION SET - The residual deformation of a material after removal of the compressive stress. CURE - The act of vulcanization. DUMBBELL - A dog bone shaped flat specimen of rubber used for te
27、sting of physical and chemical properties. ELASTOMER - This term is used synonymously with rubber, particularly synthetic rubber; generally a non- metallic material which resists deformation, up to a point, and has the ability to recover its original shape after the deforming force is removed. See R
28、UBBER. ERG - Energy Rubber Group. EXPLOSIVE DECOMPRESSION - A type of seal failure manifested by gas bubbles, blisters, cracks, etc., on the surface of a seal or internally in a seal which has been exposed to high gas pressure and then subjected to a rapid release of pressure. EXTRUSION (Processing)
29、 - One of the methods to form rubber and plastic materials into usable shapes, such as gaskets, seals, etc. EXTRUSION - One of the common modes of failure of seals. This usually refers to the flow of rubber seal particles into the gap between a piston and cylinder. FIELD - In this text: the oilfield
30、. FLUOROELASTOMER - Fluorine-containing elas- tomer: Common examples are trademarked VITON, FLUOREL, KALREZ, CHEMRAZ, and AFLAS. GAS DEFUSION - Gas penetration through a seal material, usually under high pressures: see EXPLO- SIVE DECOMPRESSION. HNBR - Hydrogenated acrylonitrile butadiene elas- tome
31、r or HSN. HSN - See HNBR. KALREZ - See fluoroelastomer. MODULUS - The ratio of stress to strain; in the rubber industry modulus refers to the tensile stress of rubber compounds at 100 percent, 200 percent, etc., stretch. Consequently the rubber strength values are usually given at 100 percent MODULU
32、S, 200 percent MODULUS, respectively. NACE - National Association of Corrosion Engineers. NBR - Standard abbreviation of nitrile rubber (acrylonitrile-butadiene). NITRILE - See NBR. OIL AND GAS INDUSTRY - In this bulletin, the name is used in reference to the exploration and pro- duction of natural
33、gas, crude oil, and geothermal products. PACKING - A deformable material which is gener- ally less flexible than homogeneous rubber seals and energized by squeezing or compressing it by mechani- ca means; usually located in a stuffing box. P, - Critical pressure. POLYMER - A broad group of high mole
34、cular weight materials which includes rubber, elastomers, and plastics. PLASTIC (Packing) - Various soft materials used to inject behind or around a certain type of seal and there- by to hydraulically energize it. The plastic itself is usu- ally not intended to be a sealant. PLASTICS - Synthetic, mo
35、ldable, castable, pliable material with some elastic properties. In seal technol- ogy, plastics are often used for backup rings and antiextrusion devices. RUBBER - Natural or synthetic, pliable material with elastic, and springy properties, often stretchable to several times its original length, and
36、 with the ability to recover the original length. Rubber is always used in a mixture with other ingredients in order to make it moldable and to improve its mechanical properties; see ELASTOMER, also COMPOUND. SEAL - A device that prevents the leakage of fluids (liquid or gas) from a pressure vessel.
37、 Seal material may be elastomer, metal, plastic, or a composition of several materials. DYNAMIC SEAL - A seal where there is any one of several possible modes of relative motion between the sealing surfaces: lateral, rotary, etc. FACE SEAL - A static seal between two surfaces. ROTARY SEAL - A type o
38、f dynamic seal where the relative motion is circular. STATIC SEAL - A seal where there is no relative motion between the seal and the sealing surface. The API BULL*bJ 92 0732290 0500007 T 6 American Petroleum Institute seal may be energized by compression in the vertical or radiai direction. SOUR -
39、The presence of hydrogen sulfide (H2S) in natural gas or crude oil. SWEET - The well product contains no H2S; see SOUR. T, - Critical temperature. Tg - Glass transition temperature; below this point rubber becomes rigid, glass-like material. VITON - See fluoroelastomer. VOLUME FILL - (Also seal/glan
40、d occupancy ratio) is the ratio of seal volume to available seal groove volume, often expressed in terms of percentage. VULCANIZATION - The crosslinking of molecules of the raw rubber material; an irreversible thermo- chemical process that takes place during and/or after molding, extruding, casting
41、of raw rubber compounds. XNBR - Carboxylated nitrile. 3.2 Reference Documents. “Specification for Wellhead and Christmas Tree Equip- ment,” API Specification 6A, 16th Ed., Washington, DC., 1989. API Glossary of Oilfield Production Terminology, (Defi- nitions and Abbreviations, 1st Edition, January 1
42、988. ASTM D395-STM for Rubber Property, Compression Set. ASTM D412-STM for Rubber Properties in Tension. ASTM D471-STM for Rubber Property - Effect of Liquids. ASTM D1329-STM for Evaluating Rubber Property - Retraction at Lower Temperatures (TR Test). ASTM D1414-STM for Rubber O-rings. ASTM D1415-ST
43、M for Rubber Property - Interna- tional Hardness. ASTM 1566 - Standard Terminology Relating to Rubber. ASTM D2240 - Rubber Property, Durometer Hard- ness. ASTM D4483 - Standard Practice for Rubber - Determining Precision for Test Method Standards. NACE - TM0187-87 - Evaluating Elastomeric Mate- riai
44、s in Sour Gas Environments. NACE - Proposed Test Method, Evaluating Elasto- meric Materials in Carbon Dioxide Decompression Environments. ACS Rubber Division, Paper No. 83 - “A Users Approach to Qualification of Dynamic Seals for Sour Gas,” October 1988. ACS Rubber Division, Paper No. 44 - “Swelling
45、 of Some Oilfield Elastomers in Carbon Dioxide, Hydrogen Sulfide and Methane at Pressures to 28 MPa, October 1983. Underwriters Laboratory Inc., “UL 746B Standard for Polymeric Materials - Long Term Property Evalua- tions,” 4th Ed., 1991. SECTION 4 ENVIRONMENT 4.1 Introduction. Oilfield equipment ca
46、n be exposed to a wide variety of environments. In one instance, it is expected to work within the full range of chemical, thermal and pressure conditions in order to drill, pro- duce, process, and transport the products of gas and oil wells. In the second instance, it is expected to perform reliabl
47、y in any geographical or seasonal locale of the world - from the Tropics to the Arctic. The performance-limiting components of oilfield equip- ment are usually the seals and packings. The materials of construction of nonmetallic seals are generally lower strength and less resistant to the environmen
48、tal factors that the metallic portion of the wellheads, valves, etc. Consequently, understanding the environmental factors is of utmost importance before the material selection, the design, and the testing procedures of the sealing mechanisms are undertaken. 4.2. Chemical Environment. The following
49、list con- tains the most common fluids, both liquids and gases, found in the oilfield. It should be noted that the effect of all chemicals is dependent on the concentrations, temperature and other conditions. The effect of multi- pie chemicals and their reaction products is beyond the scope of this listing. However, the design engineer and the end user should be wary of the complexities of this possibility and should consult a chemist who is expert in this field. Primary Chemicals (Fluids - Drilling, Completion and Produced). Crude Oil Natural Gas Hydrocarbon Condensates Brine (Produced) A
