API TR 6J1-2000 pdf free download

API TR 6J1-2000 pdf free download.Elastomer Life Estimation Testing Procedures.
1 Scope Estimating the service life of elastomeric sealing elements used in severe environments, such as encountered in energy exploration and oil/gas production industries, has been extremely difficult. Elastomeric sealing elements are fre- quently exposed to methane, hydrogen sulfide, and carbon dioxide gases, along with crude oil, water and corrosion inhibiting chemicals. The proposed procedure outlines a tech- nique based on the Arrhenius principle of chemical reaction rates, which permits the life of an elastomeric material to be estimated when exposed to a severe service environment. The actual test procedure must be coordinated and agreed upon between the supplier of the equipment that incorporates the elastomer sealing elements and the end user. The procedure should be based upon a definition of the service conditions and requirements such as: a. Temperature —steady state or a high and low range of service. b. Fluids and gases —stagnant or flowing. c. Pressure —continuous or a low and high range. d. Chemicals and additives —inhibitors, descalers, acidiz- ing, etc. e. Mechanical requirements —dynamic or static, torque, set- ting force. f. Failure criteria —pressure leakage, loss of mechanical function, inability to set or retrieve. 2 References The following references are recommended as sources of additional information on the life prediction technique dis- cussed above: 1. Vicic, J.C., Testing of Polymers for Oil and Gas Appli- cations , American Chemical Society, Energy Rubber Group, 1984. 2. Abrams, P.I., Kennelley, K.J., Johnson, D.V., A User’s Approach to Qualification of Dynamic Seals for Sour Gas Environments , American Chemical Society, Rubber Divi- sion, 1988. 3. Brady, J.E., Humiston, G.E., General Chemistry Prin- ciples and Structure , Third Edition, John Wiley & Sons, 1975. 4. Underwriters Laboratories Inc., UL 746B Standard for Polymeric Materials—Long Term Property Evaluations , 2nd Ed., 1979.
3 Problem Statement 3.1 Traditional methods of evaluating elastomers used for sealing elements involve the use of ASTM or other standard immersion-type tests. In these techniques, samples of the candidate elastomeric material are immersed in the antici- pated environment for a specified time period in the free state. Immersion times can vary from hours, to weeks, to months. The samples may be in a pressurized or unpressur- ized environment. The physical properties before and after immersion are compared and a judgment is made as to the suitability of the elastomer for use in the service environ- ment. The elastomeric material is generally not tested in its end use geometry (form) and not confined to a seal gland. In a properly designed seal gland, minimal seal surface area is exposed to the severe environment, and the gland physically limits the swell of the sealing element within the gland. The use of an immersion testing technique for retained physical properties does not answer the question of how long the elas- tomeric sealing element will function as a seal in a severe environment. Many sealing elements used in the energy exploration and oil/gas production industries are expected to remain serviceable (not leak) for up to 20 years in a severe service environment.
3.2 Traditional immersion tests for retained physical prop- erties have a role in the initial screening of suitable candidate elastomeric materials. A material would not be selected for service, which was severely attacked and deteriorated by the service environment in an immersion test. However, some degradation of physical properties (stress-strain) and volu- metric swell can be tolerated. It should also be noted that cer- tain elastomeric materials may sustain minimal property degradation in an immersion test, but they still may not be suitable for long-term sealing service. This is because they exhibit excessive creep or stress relaxation at high pressures and/or temperature. 4 Life Estimation Technique—Overview 4.1 The elastomer life estimation technique described below is based on the Arrhenius principle of chemical reac- tion rates. This principle is concerned with chemical reac- tion rates and the effects of temperature on these rates. In general, for every 10°C (18°F) temperature increase, the chemical reaction rate doubles.