Elastomer Failure | Materials And Corrosion Control
| Damage Mechanism | Elastomer Failure |
Damage Description |
· Wellhead and downhole equipment employ elastometric stacks for sealing. These elastomers are designed to be compatible with multi-phase produced fluids, inhibited packer fluids and various organic or inorganic acids or chemicals for well stimulations. |
Affected Materials |
· Typical elastomers which are being used in oil and gas producing wells are nitrile, hydrogenated nitrile, polyurethane, fluorocarbon (Viton).
· The polished bore receptacles, Blow Out Preventers (BOPs) or packer assemblies typically have viton, aflas, kalrez, chemraz, and/or ryton elastomer seals · Various static and dynamic seals in pressure control equipment employ polyurethane and fluorocarbon seals. · Polyurethane is sued for coiled tubing stripper element. |
Critical Factors |
· Chemical compatibility with multi-phase produced fluids (hydrocarbons, gases and brines), chemical (acid corrosion inhibitors), and inhibited packer fluids.
· Temperature · Pressure |
Affected Units or Equipment |
· Sub-surface equipment: static and dynamic seals for BOP ram, BOP body, bottom-hole assemblies (Polished Bore Receptacle (PBR) and packer assemblies) and Coiled Tubing stripper. The PBR provides a honed ID sealing surface for a production tubing seal assembly. The PBR may be used on top of a production packer. It is used as a receptacle to accept Seal Mandrels |
Appearance or Morphology of Damage |
· Elastomers lose their mechanical properties (tensile, elongation, compression), swell or crack when they are not compatible with the fluids or chemicals, leading to losing their salability. |
Prevention/Mitigation |
· Any elastomeric seals must prove their compatibility to the produced fluids or chemical for well stimulations prior to commissioning
· Likewise, any chemicals which will be used for well stimulation should be screened out by a series of incompatibility tests with existing elastomers. |
Inspection & Monitoring |
· Visual examination (as new)
· Check mechanical properties (as new) |
Inspection Frequency |
· NA |
Key Performance Indicators (KPIs) |
· # Elastomer failure (target 0) |
Plant Integrity Windows (PIWs) |
· Not Applicable |
Competencies and Training |
Corrosion Courses · e-COE 101 Corrosion Basics · e-COE 701 Corrosion & Corrosion Prevention · PEW 407 Corrosion Technology · COE 104 Chemical Treatment for Producing Operations |
Reference Resources (Standards/GIs/BPs) |
Khairi Nagdi “Rubber as an Engineering Material: Guide for Users” by Hanser Publishers, 1993 |
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