Description
In order for Praxis Completion Technology to ensure the proper seal system is chosen, it is important to know the well conditions as well as the work to be performed. Minimum and maximum temperature, presence of hostile elements (H2S, CO2, etc.). Seal movement and pressure differential are all parameters that should be considered during the selection process. H2S and/or CO2 environments will dictate the most suitable seal material, along with certain requirements for all metallic components of the assembly; most commonly components should comply with NACE MR0175 Specifications.
These factors will determine the seal type, metal material and accessories to be utilized. For all seal bore tubing accessories, standardization of threads, seal diameters, and seal lengths have been carefully considered in the design to maximize interchangeability with competitive seal bore equipment.
The accessories are also available in several types of material with the following three as an example:
- High strength alloy steel - high pressure applications
- 9CR-MO alloy steel - H2S and CO2 applications
- Incoloy 925 alloy steel - severe corrosion applications
Two basic seal types are currently available:
- Elastomer bonded to metal commonly known as moulded seals and available in Nitrile, Viton, Flourel, EPDM, ECO, and HSN materials.
- Chevron style lip-type seals commonly known as V-Rings (not recommended to float out of seal bore) are available in Nitrile, Viton, Flourel, Teflon, Ryton, Aflas, and Kalrez materials.
Temperature, hostile elements, seal movement and pressure differential are parameters to consider when selecting seal types.
Seal Stack consists of alternate Kalrez, Teflon, and Ryton seal rings with metal end and center adapters. Recommended for maximum temperatures of 260°C (500°F), amine-based inhibitors, and high H2S and/or CO2 environments. The picture shows a Cross-Section of K/T/R Chevron Style Seal Stack.